Answer:
18 yds
Step-by-step explanation:
Let the length and width be L and W respectively.
Then L· W = area = 72 yd², so that L = (72 yd²) / W.
But also L = 3W + 6 yd. Subbing this into L· W = area = 72 yd², we get:
(3W + 6) · W = 72, or
3W² + 6W - 72 = 0. Since all four terms are evenly divisible by 3, we get:
W² + 2W - 24 = 0, which factors as follows:
(W + 6)(W - 4) = 0. Then W + 6 = 0, or W = -6 (makes no sense for a length), and W - 4 = 0 yields W = 4 yds.
If the shorter side is of length 4 yds, then the longer side is of length
L = 3(4 yds) + 6 yds = 18 yds
