The length of a rectangle is three times its width.

If the perimeter of the rectangle is 40 in, find its area.

75 in^2

Step-by-step explanation:

L = 3W here. Also, P = 2W + 2L = 40 in here. Subbing 3W for L, we get

2W + 2 (3W) = 40, or

2W + 6W = 40, or 8W = 40. Thus, W = 5 in and L = 15 in

and the area is W*L, or 5 (15) in^2, or 75 in^2