SOLUTION: If the perimeter of a rectangle is 42 cm and the area is 90 square cm, then what are the dimensions of the rectangle?

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Question 874641: If the perimeter of a rectangle is 42 cm and the area is 90 square cm, then what are the dimensions of the rectangle?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,



P = 2L +2w = 42cm

     L + w = 21  L+=+21-w

A = Lw

   (21-w)w = 90cm^2

   w^2 - 21w + 90 = 0

  (w-15)(w-6) = 0

Dimensions: 15cm by 6cm