Wednesday, May 8, 2013

A rectangle has a perimeter of 336 square inches. The length is 21 inches long. Find the width


First note that perimeter is measured in inches, and here is the formula for the perimeter of a rectangle: 
%0D%0A%0D%0AP=2%28l%2Bw%29%0D%0A
P=336, l=21

so...

%0D%0A336=2%2821%2Bw%29%0D%0A
divide by 2...

%0D%0A168=21%2Bw%0D%0A

w=168-21=147
width is 147 inches

:)

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