Requesting Help with Ratios.

Nath.Cross

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Hello all! I hope that today will/is/or has treated you kindly. I was wondering if any of you math fans could help me with a problem regarding ratios. I have three numbers.

4 and 13/16ths
7 and 2/16ths
21 and 6/16th

The number 4 and 13/16ths corresponds to a height of 5 Feet, 11 Inches.

I haven't been in a math class for over a decade and a half and due to entry-level, low-intelligence jobs that I've had in that corresponding time frame alone with no application of even the most simplest extension of basic arithmatic, my ability to do math has atrophied atrociously.

So, my question is this. If the number 4 and 13/16ths equals a height of 5 Feet, 11 Inches, what would be the height of the other two numbers.

A straight answer would be fine, but in the spirit of teaching a man to fish, if you feel like maybe providing a quick lesson regarding these numbers that would be cool too. My problem lies probably with the fact that I am using mixed units of measurement. If I were dealing with just straight numbers in a contextual vacuum, I would be able to pull this equation off. But I don't have any idea how to deal with a flat contextually-absent number with a number that is obviously a unit of measurement.

To anyone who is able and willing to respond to this post, I would appreciate the help, and if a minor lesson involving mixed units is also provided, that would be appreciated even more as it would allow me to recapture just a little bit of the massive amount of math that has long been seaping its way out of my brain due to a decade-and-a-half of non use and application.
 
So, my question is this. If the number 4 and 13/16ths equals a height of 5 Feet, 11 Inches, what would be the height of the other two numbers.

A straight answer would be fine, but in the spirit of teaching a man to fish, if you feel like maybe providing a quick lesson regarding these numbers that would be cool too. My problem lies probably with the fact that I am using mixed units of measurement. If I were dealing with just straight numbers in a contextual vacuum, I would be able to pull this equation off. But I don't have any idea how to deal with a flat contextually-absent number with a number that is obviously a unit of measurement.

To anyone who is able and willing to respond to this post, I would appreciate the help, and if a minor lesson involving mixed units is also provided, that would be appreciated even more as it would allow me to recapture just a little bit of the massive amount of math that has long been seaping its way out of my brain due to a decade-and-a-half of non use and application.
It sounds like your main issue is converting mixed numbers and mixed units to single (decimal) numbers. I'll give examples:

The mixed number 4 13/16 means 4 plus 13 divided by 16; so first divide 13 by 16, then add the resulting decimal to 4.

The mixed-unit number 5 feet 11 inches means 5 11/12 feet, so repeat the same process.

Then, if I understand correctly, you may be able to solve your problem with the resulting numbers. Please show us your attempt, so we can see if you need more help. (You might also want to show us your work for a similar problem with simpler numbers.)
 
Hello all! I hope that today will/is/or has treated you kindly. I was wondering if any of you math fans could help me with a problem regarding ratios. I have three numbers.

4 and 13/16ths
7 and 2/16ths
21 and 6/16th

The number 4 and 13/16ths corresponds to a height of 5 Feet, 11 Inches.

I haven't been in a math class for over a decade and a half and due to entry-level, low-intelligence jobs that I've had in that corresponding time frame alone with no application of even the most simplest extension of basic arithmatic, my ability to do math has atrophied atrociously.

So, my question is this. If the number 4 and 13/16ths equals a height of 5 Feet, 11 Inches, what would be the height of the other two numbers.

A straight answer would be fine, but in the spirit of teaching a man to fish, if you feel like maybe providing a quick lesson regarding these numbers that would be cool too. My problem lies probably with the fact that I am using mixed units of measurement. If I were dealing with just straight numbers in a contextual vacuum, I would be able to pull this equation off. But I don't have any idea how to deal with a flat contextually-absent number with a number that is obviously a unit of measurement.

To anyone who is able and willing to respond to this post, I would appreciate the help, and if a minor lesson involving mixed units is also provided, that would be appreciated even more as it would allow me to recapture just a little bit of the massive amount of math that has long been seaping its way out of my brain due to a decade-and-a-half of non use and application.
Hi @Nath.Cross,

I wouldn't normally dare to disagree with @Dr.Peterson but in this case I'm not sure his suggestion of converting to "
single (decimal) numbers" is the "best" way forward, either in terms of facilitating the calculations in or aiding your understanding of (& "learning" about) how to go about this problem (particularly since converting to decimal numbers produces decimal fractions that cannot be "accurately" written down; only approximated).

I would suggest that it might be more appropriate to convert your three mixed numbers into improper fractions to produce:-


4\(\displaystyle \frac{13}{16}\) = \(\displaystyle \frac{77}{16}\)      7\(\displaystyle \frac{2}{16}\) = \(\displaystyle \frac{114}{16}\)      21\(\displaystyle \frac{6}{16}\) = \(\displaystyle \frac{342}{16}\)

Now you can express your three numbers in (typical) "ratio format" as:-

\(\displaystyle \frac{77}{16}\) : \(\displaystyle \frac{114}{16}\) : \(\displaystyle \frac{342}{16}\)

but, since these (fractional) numbers all share the same denominator, you could rewrite this as simply:-

77 : 114 : 342

Again, rather than converting 5' 11" to 5\(\displaystyle \frac{11}{12}\) feet ( 5.91667 feet), I would suggest it might be more convenient/appropriate to simply convert this to (a whole number value of) inches; ie: 5\(\displaystyle \frac{11}{12}\) feet = 71 inches.

Unfortunately, since you have been presented with such awkward numbers (it would have been so much more "convenient" if the height given had been 5' 6" (or even better 6' 5" ?) instead of 5' 11"!) then I'm afraid there will have to be some approximating (or rounding) involved in your calculations but the method I'm proposing at least leaves this to the final calculations.

So, if we take our ratios and add a 1 into the expression we then get:-


1 : 77 : 114 : 342

So what height would the "1" represent?

Well, clearly, if the "77" represents 71inches then the "1" will represent (71 ÷ 77) inches. (I trust you can follow that reasoning OK?)

So, enter 71 ÷ 77 into your calculator and store the result in the memory and if you now multiply 77
(or any of the numbers in your ratio expression)
by the number in the memory you will get a good approximation
* to the height represented by the ratio(s) in inches (which I trust you can confidently convert back to feet & inches if required).

You should now be able to determine what all of the heights involved are (to within a
fraction of an inch ?)

Hope that helps. ??


*in the case of "77" you will, of course, get an exact value for the height in inches.
 
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Postscript:

The "
minor lesson" (you asked for) in my method would be:-

To convert a mixed number such as 4⅔ to an improper fraction, you multiply the integer number (4) by the denominator (3) and add the result to the numerator, thus:-


4⅔ = \(\displaystyle \frac{14}{3}\)    (4 × 3 + 2 = 14)

'Explanation': 1 = \(\displaystyle \frac{3}{3}\)   so, 2 1s = \(\displaystyle \frac{3}{3}+\frac{3}{3} = \frac{6}{3}\),   3 1s = \(\displaystyle \frac{9}{3}\),   4 1s = \(\displaystyle \frac{12}{3}\) and so on...

This is also analogous to 5ft 11in (= 5
\(\displaystyle \frac{11}{12}\) ft) = \(\displaystyle \frac{71}{12}\) ft = 71" (since an inch is one twelfth \(\displaystyle \left(\frac{1}{12}\right)\) of a foot.) ?

(That is also why it would have been soooo much better if the given height had been 6' 5" (77") because then you would have had no fractions left in your answers and they would all have been a whole number of inches! I really don't understand why whoever came up with this 'problem' didn't opt for 6' 5" (or even 5' 6") instead of the (gruesome) 5' 11" unless it's a "real life" situation where you just have to 'play the cards you're dealt with'. ?)
 
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Afterthought:-

This probably
is a "real life" situation. Now that I've had time to think about what you presented (instead of trying to answer your questions), I suspect this may be a case of you trying to 'lift' dimensions (eg: off a drawing) where you know one of them (to be 5' 11") and are using a (n 'imperial') rule that is marked in sixteenths of an inch (as they almost always are) to measure other lengths on the drawing. Hence the numbers all including sixteenth fractions.
That would explain the "messy" results obtained; "Nothing in life is simple"! (to misquote Sachar. ?)
 
It sounds like your main issue is converting mixed numbers and mixed units to single (decimal) numbers. I'll give examples:

The mixed number 4 13/16 means 4 plus 13 divided by 16; so first divide 13 by 16, then add the resulting decimal to 4.

The mixed-unit number 5 feet 11 inches means 5 11/12 feet, so repeat the same process.

Then, if I understand correctly, you may be able to solve your problem with the resulting numbers. Please show us your attempt, so we can see if you need more help. (You might also want to show us your work for a similar problem with simpler numbers.)
So, without looking at The Highlander's suggestion as I feel that may have exactly the correct answer without the challenge of me trying it for myself. Although I think that reducing to decimals might not be the best course of action here. So, here I go with "Problem 1."

4 13/16 = 5' 11. What does 7 2/16 equal.

(4 * 16) + 13 = 64 + 13 = 77/16
___________________________________
(5 * 12) + 11 = 60 + 11 = 71/12

I think the next step I would need to do is I think to convert them to have matching denominators so I think the next step would be

77/16 * 12/12 = 924/192
___________________________
71/12 * 16/16 = 1,136/192

Cutting all the fluff I get

924/192
____________
1,136/192

Now, to find out what 7 2/16 is, I turn that into a fraction with 192 as a denominator. So

(7 * 16) + 2 = 112 * 2 = 114/16

Upverting to the larger common denominator

114/16 * 12/12 = 1,368/192

So, I get the ratio of

924/192 1,368/192
____________ = ____________
1,368/192 h

Now I do just regular ratio exercises

924/192 1,368/192
__________ * ____________
1,136/192 h

Cancel out the 192's I get

924 1,368
_______ * _______
1,136 h

(1,136 * 1,368)/924 = 1,554,048/924 = 1,681.8701298701298701298701298701? Which I don't think is right. So, now I'm going to check The Highlander's response to see where I went wrong.
 
Okay, going by what The Highlander said, he/she/they suggested simplifying everything to measure in equivalent units of measure. So I opted for 16ths of an inch. So, going with problem one,

4 13/16 becomes (4*16) + 13 = 64 + 13 = 77

5 feet 11 0/16 inches becomes ((5 * 11) * 16) + 0 = (55 * 16) + 0 = 880 + 0 = 880

Now, holding onto that 77/880 fraction in my head for a moment, I'm going to convert 7 2/16 to just 16ths

7 2/16 becomes (7*16) + 2 = 112 + 2 = 114

So, my resulting ratio becomes

77/880 = 114/h

So I multiply 114 by 880 and I get 100,320.

I divide that by 77 and I get approximately 1,302.

So if I understand that 1,302 number that is how many 16ths of an Inch my resulting answer will be. So then I do the following:

1,302/16 = 81.375. So, converting that into 16ths of inches as opposed to decimals, I get 81*16 = 1,296

1,302 - 1,296 = 6.

So, in inches, my answer comes out to be 81 6/16. Now I convert the 81 inches into feet and I get 81/12 = 6.75.

6*12 = 72
81 - 72 = 9.

So, if I did the math correctly, I think the answer to:
If 4 13/16 equals 5 Feet 11 Inches, what does 7 2/16 equal is

6 Feet 9 Inches, and 6/16 of an inch. If someone could check the logic of the math I have just presented and see if they came up with an answer that is close to that measurement, then I think I am confident enough to go onto the final question of:

If 4 13/16 equals 5 Feet 11 Inches, what does 21 6/16 equal.
 
I suggested using decimals to avoid some of the complication of fractions, and because the answer will not be a nice fraction anyway. I still recommend that as a practical method, but if you choose to practice working with fraction, I can't say it's a bad idea.

Looking at the first set of work you show,
(4 * 16) + 13 = 64 + 13 = 77/16
___________________________________
(5 * 12) + 11 = 60 + 11 = 71/12

I think the next step I would need to do is I think to convert them to have matching denominators so I think the next step would be

77/16 * 12/12 = 924/192
___________________________
71/12 * 16/16 = 1,136/192
You don't need to have the same denominator to do any of the work here; that's primarily for addition and subtraction. But this work is correct, and can be used.
Cancel out the 192's I get

924 1,368
_______ * _______
1,136 h

(1,136 * 1,368)/924 = 1,554,048/924 = 1,681.8701298701298701298701298701?
The error is just in your interpretation of the answer. You canceled the 192 everywhere, so your h here is a number of 192nds! So the answer would be about 1682/192. Carry out that division, and you get 8.76 feet as your answer; convert that to feet and inches by keeping the 8 feet, and multiplying the 0.76 by 12 to get 9.12 inches. So the answer is about 8 feet, 9 1/8 inches.

A different method, without the common denominators, or using decimals, would not leave you with this confusion at the end.
 
Okay, going by what The Highlander said, he/she/they suggested simplifying everything to measure in equivalent units of measure. So I opted for 16ths of an inch. So, going with problem one,

4 13/16 becomes (4*16) + 13 = 64 + 13 = 77

5 feet 11 0/16 inches becomes ((5 * 11) * 16) + 0 = (55 * 16) + 0 = 880 + 0 = 880

Now, holding onto that 77/880 fraction in my head for a moment, I'm going to convert 7 2/16 to just 16ths

7 2/16 becomes (7*16) + 2 = 112 + 2 = 114

So, my resulting ratio becomes

77/880 = 114/h

So I multiply 114 by 880 and I get 100,320.

I divide that by 77 and I get approximately 1,302.

So if I understand that 1,302 number that is how many 16ths of an Inch my resulting answer will be. So then I do the following:

1,302/16 = 81.375. So, converting that into 16ths of inches as opposed to decimals, I get 81*16 = 1,296

1,302 - 1,296 = 6.

So, in inches, my answer comes out to be 81 6/16. Now I convert the 81 inches into feet and I get 81/12 = 6.75.

6*12 = 72
81 - 72 = 9.

So, if I did the math correctly, I think the answer to:
If 4 13/16 equals 5 Feet 11 Inches, what does 7 2/16 equal is

6 Feet 9 Inches, and 6/16 of an inch. If someone could check the logic of the math I have just presented and see if they came up with an answer that is close to that measurement, then I think I am confident enough to go onto the final question of:

If 4 13/16 equals 5 Feet 11 Inches, what does 21 6/16 equal.
Hi (again) @Nath.Cross,

Using the method I suggested, I entered 71 ÷ 77 into my calculator and got the result 0.922077922 on my display. I then stored this in the calculator’s memory because it will be held more accurately there which is why I suggested doing so.

If you enter 0.922077922 into your calculator and multiply it by 77 then the result will be 70.999… (instead of 71) whereas if you press “Recall Memory” and multiply that by 77 you will get exactly 71 (if your calculator is any good ?).

Rounding the 0.922077922 to even fewer decimal places (eg: 0.9221 or 0.922) will increase the rounding errors even further; that is why I offered my method as being ‘better’ since it leaves rounding/approximating to the final answer.

So, having now stored 71 ÷ 77 in my calculator’s memory, I can now simply multiply 114 by the stored value to get: 105.1168831 (on my display) inches.

Dividing by 12, that converts to: 8.75974026 feet

Subtracting the 8 and multiplying (the remaining 0.75974026) by 12, I arrive at (a balance of): 9.116883117 inches.

And (if you really want/need the sixteenths) subtracting the 9 and multiplying by 16, I get: 1.870129872 sixteenths of an inch which I would then round to 2 sixteenths of an inch (and that would be the only rounding/approximating involved in my method).

So, the “
7 2/16” number (length?) represents: 8 ft 9\(\displaystyle \frac{2}{16}\) in not, I’m afraid, your answer of : 6 ft 9\(\displaystyle \frac{9}{16}\) in.

You went way off course right at the outset by wrongly converting the 5’ 11” to 880 sixteenths of an inch!
5’ 11” is 77” (as I showed in my first response) and 77” is 1,232 (77 × 16) sixteenths of an inch (not 880 as you arrived at!).

I noticed a couple of further errors on the next few lines too, so I haven’t worked through any further of your calculations since that (fatal) error at the outset will carry through and invalidate all further results but your “method/approach” does seem rather “heavy handed” (compared to what I suggested).

As you can (hopefully now) see, the above ‘procedure’ does (also) allow for arriving at the calculated lengths including sixteenths of an inch (if desired).

I had not envisaged this in my original post (as it seemed unnecessary) but, as illustrated above, it involves only one further short calculation.

(IMNSHO) It’s only more complicated (and therefore more likely to be subject to error) to work in sixteenths of an inch rather than just inches but you are perfectly free to do whatever you wish.

I had hoped that you would understand and appreciate the 'simplicity' of the approach I provided (over my three posts) and I now suggest you, perhaps, have another look at the method I offered (to make sure you understand it) and adopt the procedure outlined in this post for your final calculation of the length that corresponds to the “
21 6/16” element in the ratios.

Hope that helps (this time). ??

Don’t look at the ‘third length’ revealed under this spoiler until you’ve tried to get it yourself?
21 6/16 → 26ft 3\(\displaystyle \tiny\frac{6}{16}\)in. (to the nearest sixteenth of an inch).
 
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One final (?) note:-

If your (known) length had been 5 feet 11
\(\displaystyle \frac{x}{16}\) inches then it would have been necessary to work in sixteenths of an inch but since it was equivalent to a whole number of inches that is why the ratios (1:77:114:342) can be safely arrived at and used to calculate the corresponding lengths in (decimal*) values of inches (rather than sixteenths of an inch) but you're entitled to do whatever 'floats your boat', of course. ?

The important point about this method is the inclusion of the "1" in the ratios which then allow you calculate a "multiplier" value (0.922077922 but safely stored in memory as 71 ÷ 77!) that enables the calculation of all the other lengths "directly" before conversion back to ft/in etc.

* which you then convert back to feet & inches (& sixteenths of an inch if really necessary?) using the procedure illustrated above.
 
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(SNIP)

Subtracting the 8 and multiplying (the remaining 0.75974026) by 12, I arrive at (a balance of): 9.116883117 inches.

And (if you really want/need the sixteenths) subtracting the 9 and multiplying by 16, I get: 1.870129872 sixteenths of an inch which I would then round to 2 sixteenths of an inch (and that would be the only rounding/approximating involved in my method).

So, the “
7 2/16” number (length?) represents: 8 ft 9\(\displaystyle \frac{2}{16}\) in not, I’m afraid, your answer of : 6 ft 9\(\displaystyle \frac{9}{16}\) in.

(SNIP)

I noticed a couple of further errors on the next few lines too, so I haven’t worked through any further of your calculations since that (fatal) error at the outset will carry through and invalidate all further results but your “method/approach” does seem rather “heavy handed” (compared to what I suggested).

(SNIP)
Okay, first off, thank you VERY much for pointing out the "Fatal" error that I had made. I also retried using your method and I got something that was VERY close to what you got. Due to maybe differences in rounding, I was able to come out to the answer of 8 Feet 9 Inches and 1/16ths of an inch. So, I'm going to try and do this again to my next problem of "What Does 21 6/16ths Equal?"

So, starting number is
4 13/16 = (4 * 16) + 13 = 64 + 13 = 77

The related height is 5' 11" so:
((5 * 12) + 11) * 16 = (60 + 11) * 16 = 71 * 16 = 1,136

So my first fraction is
77/1,136

I now need to convert the 21 6/16 so:
(21 * 16) + 6 = 336 + 6 = 342

Meaning my second fraction is 342/h

So my ratio I am now working with is:

77 342
_____ X ______
1,136 h

(342 * 1,136) / 77 = 388,512 / 77 = (APPROX.) 5,045

So that 5,045 corresponds to 5,045/16. I am now going to turn that into a proper fraction:
315 5/16

But that doesn't tell me anything so, I will now convert that 315 to Feet:
26 Feet.

So if I properly followed your tutelege and assuming I didn't make any mistakes, the answer to my question of:

If 4 13/16 Equals 5 Feet 11 Inches, What Does 21 6/16 Equal?

Should be:

26 Feet, 3 Inches and 5/16.

I hope. Have I learned anything or did I mess up again, just in a different way this time?
 
You are very resistant aren't you? ?

The method you have followed is not that which I have tried to encourage you to use but you seem to be determined to persevere with yours even though it is producing the wrong answers (principally due to the 'early rounding' that I tried to warn you against) so I will go over what you say and try to show you again how to simplify the process. Both of the answers in your post are out by a sixteenth of an inch. Not much, perhaps, but, since you are determined to work to that level of 'accuracy', I trust you will agree that even that small(?) error is not really acceptable?

Okay, first off, thank you VERY much for pointing out the "Fatal" error that I had made. I also retried using your method and I got something that was VERY close to what you got. Due to maybe differences in rounding, I was able to come out to the answer of 8 Feet 9 Inches and 1/16ths of an inch. So, I'm going to try and do this again to my next problem of "What Does 21 6/16ths Equal?"
As @Dr.Peterson and I have both shown you, the correct answer is "8 feet, 9 1/8 inches" (courtesy of DrP in Post #8) or "8 ft 9\(\displaystyle \frac{2}{16}\) in" which I showed you (in detail) how to calculate my easy way in Post #9.
So, starting number is
4 13/16 = (4 * 16) + 13 = 64 + 13 = 77 Yes, if you insist on doing it this way.

The related height is 5' 11" so:
((5 * 12) + 11) * 16 = (60 + 11) * 16 = 71 * 16 = 1,136 Agreed, if you must work in sixteenths.

So my first fraction is I'll go along with that although I would have put it as 1,136/77 (but that's just 'preference.)
77/1,136

I now need to convert the 21 6/16 so: OK
(21 * 16) + 6 = 336 + 6 = 342

Meaning my second fraction is 342/h Sure

So my ratio I am now working with is:

77 342
_____ X ______
1,136 h
No, no, no, no!

What you should be "working with" is:-

\(\displaystyle \frac{77}{1,136}=\frac{342}{h}\)
The two fractions you have constructed are equivalent to each other (hence the = sign); they are not to be multiplied!

So rearranging, you get: \(\displaystyle \frac{77}{1,136}=\frac{342}{h}\Rightarrow h=\frac{1,136 × 342}{77}\)

Which (somehow) you did arrive at! (Perhaps you are just writing in the wrong arithmetic operator but somehow 'know' what you're trying to do?)
(342 * 1,136) / 77 = 388,512 / 77 = (APPROX.) 5,045
Now this is where you are going wrong! I have repeatedly tried to encourage you NOT to approximate/round until you get to your very last calculation result!
So that 5,045 corresponds to 5,045/16. I am now going to turn that into a proper fraction:
315 5/16 (Huh???)

But that doesn't tell me anything so, I will now convert that 315 to Feet:
26 Feet. (If 315 is inches then it is equivalent to 26' 3" not 26 feet!)
I have absolutely no idea what you are doing in those two lines!
So if I properly followed your tutelege (I'm sorry to say you really didn't) and assuming I didn't make any mistakes, the answer to my question of:

If 4 13/16 Equals 5 Feet 11 Inches, What Does 21 6/16 Equal?

Should be:

26 Feet, 3 Inches and 5/16. (Did you not look under the "Spoiler button" I put near the end of Post #9? You are out by one sixteenth again.)

I hope. Have I learned anything or did I mess up again, just in a different way this time?
So, lets see if we can get the right answer (your way).
For the remainder of this section, all the numbers are just what are displayed on my calculator; I am not writing them down anywhere or re-entering them into the calculator, all the calculations shown just follow on from each other on the calculator!
If we start with the rearranged fraction equivalence...


\(\displaystyle h=\frac{1,136 × 342}{77}=5045.61039\) (sixteenths of an inch!)

So, 5045.61039 ÷ 16 = 315.3506494 inches.
Subtracting the 315, we can do 0.350649351 × 16 = 5.610389616 6 (sixteenths of an inch) which is the remaining (fractional) part of the inches figure.
[Note how the “.350649
4” (2 lines above) ‘changes to “.350649351” (1 line above) because the calculator works to a greater degree of accuracy than it displays!]
Now we can do: 315 ÷ 12 = 26.25 feet.
and subtracting the 26, 0.25 × 12 = 3 inches to give us the final answer of: 26 ft 3\(\displaystyle \frac{6}{16}\) in (correct to the nearest sixteenth of an inch).

I wanted to continue in this post to show you again my way of doing this in an attempt to illustrate how much simpler it is but the site is 'playing up’ (very badly) and I’ve had to bounce all around the world (using a VPN) to get this far! So I will just post what I’ve written so far and continue in a new post once the site has settled down again either in the next hour or so or tomorrow (for me) if it still isn’t working properly.
 
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If 4 13/16 Equals 5 Feet 11 Inches, What Does 21 6/16 Equal?
Should be:
26 Feet, 3 Inches and 5/16.
Hi Nath.Cross. That result matches my approximation. I'd calculated the Feet per Number ratio from the given correspondence and then multiplied the numbers to be converted by that.

Given: (5+11/12) Feet corresponds to Number (4+13/16)

(5+11/12) = 71/12
(4+13/16) = 77/16

Feet/Number = (71/12)÷(77/16) = (71/12)×(16/77) = 284/231

To convert (7+2/16) and (21+6/16), convert them to improper fractions and then multiply by the Feet per Number ratio:

(7+2/16) = 57/8
(57/8)×(284/231) = 1349/154 ≈ 8.7597 feet (0.7597×12≈9.125 inch)
(7+2/16) corresponds to 8 feet 9⅛ inch

Likewise (21+6/16) = 171/8
(171/8)×(284/231) = 4047/154 ≈ 26.2792 feet (0.2792×12≈3+5/16 inch)
(21+6/16) corresponds to 26 feet 3 and 5/16 inch

:)
[imath]\;[/imath]
 
Hi Nath.Cross. That result matches my approximation. I'd calculated the Feet per Number ratio from the given correspondence and then multiplied the numbers to be converted by that.

Given: (5+11/12) Feet corresponds to Number (4+13/16)

(5+11/12) = 71/12
(4+13/16) = 77/16

Feet/Number = (71/12)÷(77/16) = (71/12)×(16/77) = 284/231

To convert (7+2/16) and (21+6/16), multiply them by the Feet per Number ratio:

(7+2/16) = 57/8
(57/8)×(284/231) = 1349/154 ≈ 8.7597 feet (0.7597×12≈9.125)
(7+2/16) corresponds to 8 feet 9⅛ inch

Likewise (21+6/16) = 171/8
(171/8)×(284/231) = 4047/154 ≈ 26.2792 feet
(21+6/16) corresponds to 26 feet 3+5/16 inch

:)
[imath]\;[/imath]
Your answers are out by the same sixteenth as his.
(See my post #12 above.)
 
You are very resistant aren't you? ?

The method you have followed is not that which I have tried to encourage you to use but you seem to be determined to persevere with yours even though it is producing the wrong answers (principally due to the 'early rounding' that I tried to warn you against) so I will go over what you say and try to show you again how to simplify the process. Both of the answers in your post are out by a sixteenth of an inch. Not much, perhaps, but, since you are determined to work to that level of 'accuracy', I trust you will agree that even that small(?) error is not really acceptable?


As @Dr.Peterson and I have both shown you, the correct answer is "8 feet, 9 1/8 inches" (courtesy of DrP in Post #8) or "8 ft 9\(\displaystyle \frac{2}{16}\) in" which I showed you (in detail) how to calculate my easy way in Post #9.

No, no, no, no!

What you should be "working with" is:-

\(\displaystyle \frac{77}{1,136}=\frac{342}{h}\)
The two fractions you have constructed are equivalent to each other (hence the = sign); they are not to be multiplied!

So rearranging, you get: \(\displaystyle \frac{77}{1,136}=\frac{342}{h}\Rightarrow h=\frac{1,136 × 342}{77}\)

Which (somehow) you did arrive at! (Perhaps you are just writing in the wrong arithmetic operator but somehow 'know' what you're trying to do?)

Now this is where you are going wrong! I have repeatedly tried to encourage you NOT to approximate/round until you get to your very last calculation result!

I have absolutely no idea what you are doing in those two lines!

So, lets see if we can get the right answer (your way).

For the remainder of this section, all the numbers are just what are displayed on my calculator; I am not writing them down anywhere or re-entering them into the calculator, all the calculations shown just follow on from each other on the calculator!
If we start with the rearranged fraction equivalence...


\(\displaystyle h=\frac{1,136 × 342}{77}=5045.61039\) (sixteenths of an inch!)

So, 5045.61039 ÷ 16 = 315.3506494 inches.
Subtracting the 315, we can do 0.350649351 × 16 = 5.610389616 6 (sixteenths of an inch) which is the remaining (fractional) part of the inches figure.
[Note how the “.350649
4” (2 lines above) ‘changes to “.350649351” (1 line above) because the calculator works to a greater degree of accuracy than it displays!]
Now we can do: 315 ÷ 12 = 26.25 feet.
and subtracting the 26, 0.25 × 12 = 3 inches to give us the final answer of: 26 ft 3\(\displaystyle \frac{6}{16}\) in (correct to the nearest sixteenth of an inch).

I wanted to continue in this post to show you again my way of doing this in an attempt to illustrate how much simpler it is but the site is 'playing up’ (very badly) and I’ve had to bounce all around the world (using a VPN) to get this far! So I will just post what I’ve written so far and continue in a new post once the site has settled down again either in the next hour or so or tomorrow (for me) if it still isn’t working properly.
I think one problem that I have that is also a problem that you are having with me is that I have forgotten so much in terms of mathematics. Literally, aside from the basic arithmetic of addition, subtraction, multiplication, and division, ratios are the most advanced application of mathematics that I can remember. And what I remember was taught to me back in Middle School or so. What little I can remember of those classes was the following:

I have the first ratio:
1
___
4

and the second ratio that I need to solve for:

5
____
h

To find out h I needed to multiply the denominator of the first ratio with the numerator of the second ratio, and then divide that answer by the numerator of the first ratio.

So:

1 5
____ * _____
4 h

or

(4 * 5) / 1 = 20 / 1 = 20

Therefore, If 1 is equal to 4 than 5 is equal to 20.

Another problem that you and I might be facing is our intent in things. I guess to peel back the curtain, maybe it's time to tell you what this is for.

I have 2 action figures in my collection, one with a rather large "pompadour" shall we say, and one that's just flat out WYSIWYG. On a day of way too little to do and way too much introspection, I was wondering, if the pompadoured figure was scaled to a point where the top of its face was at the same height as mine, 5 Foot 11 Inches, how tall would the scaled up figure be if I were to measure to the top of its pompadour. Then, because my autistic mind couldn't stand to leave well enough alone, I also wondered what the height of my tallest figure in my collection would be if it were to be scaled up porportionally according to the results I got with the first figure.

So I used the only tape measure I could find in my house that measured only in feet and inches. Now because this is something as inconsequental as scaling up the size of stupid action figures, and not a question in an exam book or a job, or something like life or death, I look at being just a sixteenth of an inch off in my final result as hey, that came to be pretty damn close.

A third issue is the way I am typing out some of these equations. I have no idea how to make the fraction 4/5 look like the way you've got your fractions displayed. So that 315 5/16 that you are going "Huh???" about is supposed to be displayed as the whole number of 315 followed by the fraction of 5/16, corresponding to the measurement of 315 and 5/16ths of an inch.

However, if you say that the correct answer to my ultimate question is 26 Feet and 3 6/16 of an Inch and the answer that I came up with 26 Feet and 3 5/16 Inches, then I must have learned something from you as before I made this thread, I had NO idea how to even begin finding out the answer to this question using my own pen and paper.

You were also correct about something else. I am indeed a stubborn idiot. I haven't used my mind really at all in the past decade and a half. I used to be fairly intelligent, but over a decade and a half of not exersizing my brain has left my mind in a state where ratios are the most complicated thing I can remember and even that is getting a little foggy for me now. Couple that with my autism and you've got a perfect storm of stubborness and idocy. I'm sorry if I stressed you out at all. I really do thank you for getting me to this point because, as I said before, I needed to register on this forum because I simply didn't know how to structure my question in a way that would get me to the starting point of solving it. But thanks to you, I was able to come away with an answer that is only 1/16th of an inch off. That's awesome, and you DID teach me something or else, I wouldn't have been able to get that answer. I do graciously thank you VERY much for your patience and understanding. You did indeed help me.
 
Hi @Nath.Cross,

The site appears to be working again so let me have one final attempt to encourage you to use the ‘method’ I suggested at the outset.

We established (or, at least, I thought we had) that the ratios involved here are:-


77:114:342

Where the 77 ’represents’ a length of 5’ 11” (ie: 71”) and you wanted to find out what length the other numbers in the ratios represented.

I suggested adding a
1 to the ratios so that they became:-


1:77:114:342

Now, since you know that the 77 represents 71” then you can calculate how many inches the 1 represents by simply dividing 71 by 77.

To illustrate that (in the fashion you seem to be most 'familiar' with) we could write:-


\(\displaystyle \frac{h}{1}=\frac{71}{77}\Rightarrow h=\frac{1 × 71}{77}=\frac{71}{77}\)

or, if you prefer,

\(\displaystyle \frac{1}{h}=\frac{77}{71}\Rightarrow h × 77 = 1 × 71\Rightarrow h=\frac{71}{77}\)

So (71 ÷ 77) will give you an answer for how many inches the 1 in our ratio string represents and once you know that you can easily work out what any of the other numbers in the ratio string represents by simply multiplying them by the number of inches the 1 represents (ie: 71 ÷ 77 inches).

The simplest example is the
77. How many inches does that represent?

Well, 77 × (71 ÷ 77) = 71 and we know that is correct because that’s exactly where we started, ie: the
77 represents 71”.

So if we multiply the
114 and the 342 by (71 ÷ 77) then we will easily discover how many (inches) those numbers represent too!

Now I know you (desperately
?) want to work in sixteenths of an inch but, since your given length (5’ 11”) is a whole number of inches, it is really not necessary, in fact it may even be disadvantageous (as well as ‘complicating’ the numbers by making them overly large), to try to convert everything to sixteenths of an inch at the start of your calculations.

Because the numbers involved will necessarily lead to non-whole number results, there will have to be some rounding involved at some point but it’s always best to leave that to the very end of your calculation stream.

Once you have a final result (in inches) the (decimal) fractional part of that answer will allow you to determine how many sixteenths of an inch are involved as well as how many feet & inches are too.

So here’s the procedure…

[I presume you have and are using a calculator for this exercise. I have tried (throughout) to stress that, once you start your calculation, it should be completely carried out on the calculator without entering any further ‘values’ into it (other than the 12 & 16 you need to multiply/divide by at some stage) or writing down any ‘interim’ results for "later use". The numbers I have shown below are those that were displayed on my calculator; I expect they will be the same on yours but, of course, cannot guarantee that.]

We start by entering 71 ÷ 77 into the calculator and pressing the = button to get our result. It is vitally important to now store that result in the calculator’s memory (where it will be held more accurately than what is displayed on the calculator’s ‘screen’).

Now we can begin with the
77

Enter 77 and press times (×) then Recall Memory (an RM button?) amd press =.

Your display should show: 71 (inches) ie: 5’ 11” which we know to be correct!

Moving on to the
114

Enter 114 and press times (×) then Recall Memory =.

Your display should now show: 105.1168831 (inches)

Subtract the 105 to get: 0.116883117 (note how there are more decimal places showing up now)

Do 0.116883117 × 16 = 1.870129872 ≈ 2 (sixteenths of an inch)

(This is the only rounding that needs to be done!)

Now do 105 ÷ 12 = 8.75 (feet)

So your (whole) number of inches converts to 8 feet plus 0.75 feet (ie: 9 inches)

Final answer (for the
114) is, therefore: 8 ft 9\(\displaystyle \frac{2}{16}\) in (or 8 ft 9\(\displaystyle \frac{1}{8}\) in).

And finishing with the
342

Enter 342 and press times (×) then Recall Memory =.

Your display should now show: 315.3506494 (inches)

Subtract the 315 to get: 0.350649315 (again, more decimal places show up.)

Do: 0.350649315 × 16 = 5.610389616 ≈ 6 (sixteenths of an inch)

Now do 315 ÷ 12 = 26.25 (feet)

So your (whole) number of inches converts to 26 feet plus 0.25 feet (ie: 3 inches)

Final answer (for the
342) is, therefore: 26 ft 3\(\displaystyle \frac{6}{16}\) in.

This (explanation) has been way more wordy than what’s involved in actually carrying out the calculations but I hope it may have convinced you that this is, if not the best way to go about it, then certainly one of the simplest ways (once you’ve got the hang of it
?).

I hope that clears up any doubts in your mind about what the correct answers you’re after are and trust this has been of some interest and ‘educational' value?

Cheers
 
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