Fnd the length and width of a rectangle

Question

The length of a rectangle is 9 ft longer than twice the width. If the perimeter is 66 ft, find the length and width of the rectangle.

Answer 1

First, choose your variables. Let L be length and W be width.

L = 2W+9

Perimeter = 2L + 2W = 66

 

I will use reduction/elimination method to solve for L and W

L - 2W - 9 = 0

2L + 2W -66 = 0

Add these two equations together

3L - 75 = 0

Solving for L

L = 75/3 = 25

 

By rearranging the first equaion,

W = (L-9)/2

W = (25-9)/2

W = 16/2 = 8