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# Perimeter Formula

by Calum
(U.K)

The length of a rectangle is 4 times the width.
The perimeter of the rectangle is 80cm.
Find the length of each side.

Average Rating

 Sep 16, 2010 Rating Perimeter Formula by: Karin Hi Calum, For this problem, you must know from prior knowledge that the formula for perimeter of a rectangle is: 2L + 2W = P. We know the length is 4 times the width, but we don't know the width, so we are going to assign a variable to the width. Let w = width of the rectangle L = 4w Therefore, the length is 4w. (4 times the width) Now we'll substitute. 2L + 2W = P 2(4w) + 2w = 80 Now we'll simplify and solve for w. 8w + 2w = 80 10w = 80 10w/10 = 80/10 w = 8 The width is 8 cm and the length is 4 times the width which is 32 cm. I hope this helps, Karin

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