My basement has an area of 5,120 square feet. The width of the basement is 4/5 its length. What is the length of basement

A = L * W

W = 4/5L

5120 = L (4/5L)

5120 = 4/5L^2

5120 * 5/4 = L^2

6400 = L^2 ... take the square root of both sides, eliminating the ^2

sqrt 6400 = L

80 = L ... length is 80 ft <===

W = 4/5L

W = 4/5 (80)

W = 64 ... width is 64 ft