The length of a rectangle is three times its width. If the area of the rectangle is 147 in2 , find its perimeter.

Question

The length of a rectangle is three times its width.
If the area of the rectangle is
147

in2
, find its perimeter.

Answer 1

Write 2 equations:

 

From the 1st sentence:

L = 3W

 

From the 2nd sentence:

L * W = 147

 

Sub #1 into #2   (replace L with 3W)

3W * W = 147

 

simplify and solve:

3W^2 = 147

W^2 = 147/3 = 49

W = 7

 

From the 1st equation:

L = 21

 

Perimeter (P) = 2W + 2L = 14 + 42 = 56