Stumped on Word Problem Homework... Please Help!!!!

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middleschoolmath

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Dec 3, 2012
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Good Afternoon,
The perimeter of a rectangle is equal to 280 meters. The ratio of its length to its width is 5:2. Find the length of the rectangle. Thanks in advance......:D
 
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From the statement "The ratio of its length to its width is 5:2," we may state:

\(\displaystyle \dfrac{L}{W}=\dfrac{5}{2}\)

Solve for \(\displaystyle L\), then plug in the given value for \(\displaystyle W\).
 
We have:

\(\displaystyle \dfrac{L}{W}=\dfrac{5}{2}\)

Multiply both sides by \(\displaystyle W\):

\(\displaystyle L=\dfrac{5}{2}W=\dfrac{5}{2}\cdot280\text{ m}=?\)
 
middleschoolmath said:
Ok, thanks. Is this correct?


L = 5
W 2

280 = 5
W 2
Click to expand...

No, its not. You have replaced the length, L, with 280 but you have no reason to think that L is 280. You were told that the perimeter is 280 m. Do you know what "perimeter" means? Do you know a formula conecting the perimeter of a rectangle with the length and width? MarkFL says "plug in the given value for W", but there is NO "given value for W". He must have misread the problem. You can replace W with its expression in terms of L and the perimeter, 280.
 
Yes, haste makes waste! I did misread the problem, very sorry about that.

So, as HallsofIvy stated, you need to first state an expression for the perimeter in terms of the length and width and equate that to 280 m.

I would suggest drawing a rectangle, label the 4 sides appropriately, and add up the resulting sides (this is the perimeter, the sum of the lengths of the sides) and set this equal to 280 m. Then you may replace the width using the given ratio, and you will have an equation in L, from which you can determine its value.
 
Yes, haste makes waste! I did misread the problem, very sorry about that.
Click to expand...

No, you did not misread this problem. The student edited it without pointing out his/her change to you.
 
wjm11 said:
No, you did not misread this problem. The student edited it without pointing out his/her change to you.
Click to expand...

Thank you for letting me know this. While I certainly have made such mistakes in the past, it is nice to know this time wasn't one of them! :D
 
wjm11 said:
No, you did not misread this problem. The student edited it without pointing out his/her change to you.
Click to expand...

This is one of the reasons why I tend to "reply with quote".
 
Last edited by a moderator:
The perimeter of a rectangle is all sides added up together.

--------------
So for example:
If you have a rectangle with length of 200 and a width of 40,
the perimeter would be 200+40+200+40, which is 480.
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Now, for your problem you know that the ratio between the length and width is 5:2.
As stated by others:
L/W = 5/2.

Now you also have to find another equation to solve L and W.
I suggest you find an equation for the perimeter of this rectangle. The equation for the perimeter is then equal to 280 since that is given in your problem.

Now you have 2 equations,
Make L or W free in the first equation and plant it in the second equation you have set-up for the perimeter. (L = .... or W = ...)

Then solve and done. Let us know if you find an answer.
 
Isn't that what poor ol' Charlie Brown says when Lucy snaps the football away right before he tries to kick it?

She got hers though in a Family Guy episode...hehehe...I roared with approval! :D
 
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