Pool width 18.5 ft, length 10.75 ft: Find ratio of length to

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KV

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Mar 25, 2007
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One question that has come up yet again that I am confused about is:

The width of a swimming pool is 18.5 ft and the length is 10.75 ft. Write the ratio of the length to width as a ratio of whole numbers.

To me the answer is 11/19. The answer the teacher says is correct is 43/74. How can that be right?
 
Because:

\(\displaystyle \L\\18.5=\frac{37}{2}\)

\(\displaystyle \L\\10.75=\frac{43}{4}\)


So, \(\displaystyle \L\\\frac{\frac{43}{4}}{\frac{37}{2}}=\frac{43}{4}\cdot\frac{2}{37}=\frac{43}{74}\)
 
Re: Totally Confused

Hello, KV!

How did you get \(\displaystyle \frac{11}{19}\) ??


We have: \(\displaystyle \L\:\frac{10.75}{18.5}\)

Multiply top and bottom by 100: \(\displaystyle \L\:\frac{100}{100}\,\times\,\frac{10.75}{18.5} \:=\:\frac{1075}{1850}\)

Reduce: \(\displaystyle \L\:\frac{\not{25}\,\times\,43}{\not{25}\,\times\,74} \:=\:\frac{43}{74}\)

 
No where does it say to make a fraction of it. You round it off and you get 11/19.
 
11/19 is a ratio. take away the .5 and the .75 and the ratio would be 10/18 no making fractions of them.
 
I would you take away the .5 and .75?. That isn't the problem.

The pool is 18.5 by 10.75. Not 18 by 10. What has compelled you to do that?.
 
Was proving a point but you did not understand so just forget it.
 
KV said:
Was proving a point but you did not understand so just forget it.
Click to expand...

I'm sorry. I don't understand what point you're trying to prove.

If you are to find the ratio of 18.5 to 10.75, then you've been shown EXACTLY what mathematical steps you are to take.

The easiest way (to repeat what another responder posted), is to write

18.5
-----
10.75

To eliminate the decimals, multiply numerator and denominator by 100:

(18.5)*100
----------
(10.75)*100

1850
------
1075

Then reduce the fraction.


If you eliminate the decimals to begin with (as you seem to be suggesting when you say "take away the .5 and the .75,") you are CHANGING the problem.

Trust me....this is generally not a good idea (UNLESS you are looking for an ESTIMATE.....)
 
Re: Pool width 18.5 ft, length 10.75 ft: Find ratio of lengt

KV said:
The width of a swimming pool is 18.5 ft and the length is 10.75 ft. Write the ratio of the length to width as a ratio of whole numbers.
To me the answer is 11/19.
Click to expand...
11 and 19 are simply the rounded values of 10.75 and 18.5;
has NOTHING to do with ratios.
 
Unless you are asked to estimate (in these days of calculators/computers) - leave the rounding till the last step.

In elementary mathematics, rounding (without explicit instruction) is not a good idea.
 
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