SOLUTION: The length of a rectangle is 20cm greater than its width. The perimeter is 360cm. What is the area? I really don't understand this, could someone please help?

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Question 120556: The length of a rectangle is 20cm greater than its width. The perimeter is 360cm. What is the area?
I really don't understand this, could someone please help?
Answer by tutor_paul(519) About Me  (Show Source):
You can put this solution on YOUR website!
The perimeter (P) of a rectangle is:
P=2l%2B2w where l=length and w=width.
Based on the information given, we can use this equation to determine the sides of the rectangle, and from that, we can get the area.
Re-write the Perimeter equation based on the information given:
360=2%28w%2B20%29%2B2w
Solve for w:
360=2w%2B40%2B2w
4w=320
w=80
Now that you have w, you can easily find l:
l=w%2B20
l=80%2B20
l=100
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So now you have the length and the width - this is what you need to find the area, since the equation for the area of a rectangle is:
A=l%2Aw
Substituting in:
A=100%2A80
highlight%28A=8000%29 cm^2
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Good Luck,
tutor_paul@yahoo.com