SOLUTION: The perimeter of a rectangle is 30 inches, and its area is 36 in2. Find its length and width.

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Question 363339: The perimeter of a rectangle is 30 inches, and its area is 36 in2. Find its length and width.
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
2l +2w = 30, or l+w = 15. we have l = 15 - w.
Also, area is lw = 36. By direct substitution, (15 - w)w = 36.
15w+-+w%5E2+=+36,
w%5E2+-+15w%2B36+=+0,
%28w-3%29%28w-12%29+=+0,
w = 3 or w = 12. The rectangle is 3"x 12".