Let L ft be the length of the shorter leg.
Length of longer leg = L + 9
Length of hypotenuse = (L + 9) + 9 = L + 18
By Pythagorean theorem,
L^2 + (L + 9)^2 = (L + 18)^2
2L^2 + 18L + 81 = L^2 + 36L + 324
L^2 - 18L - 243 = 0
(L - 27)(L + 9) = 0
L = 27 or L = -9 (rejected)
Therefore the shorter leg is 27 ft, longer leg is (27 + 9) ft = 36 ft, hypotenuse = (27 + 18) ft = 45 ft.