Find the dimensions of a rectangular box of 720 cubic inches of volume such that the width is three times as big as the height and the length is 11 in. more than the height. Solution V = 720 = W*L*H 720 = (3H)(H+11)*H = 3H^2(H+11) = 3H^3 + 33H^2 you have to try some numbers to find H = 4 and then W = 12, L = 15..