The length of a rectangle is 12 in. more than its width. The perimeter is 64 in. Determine the length of the rectangle in inches.

P = 2 (L+W)

L = 12+W

P = 64 inches

64 = 2 (12+W+W)

64 = 2 (12+2W)

64 = 24+4W

64-24 = 4W

40 = 4W

W = 10 inches

L = 12+W

L = 12+10

L = 22 inches

The formula to use in determining the perimeter of a rectangle is:

2L + 2W = P

In this problem, we let x be the width and the length be x + 12.

2 (x + 12) + 2x = 64 in

2x + 24 + 2x = 64 in

4x + 24 = 64 in

4x = 64 in - 24 in

4x = 40 in

x = 10 in

The determine the length,

10 + 12 = 22 inches