Answer:
base = 17.71 ft
height = 9.71ft
Explanation:
Since we are not given the base and heigh directly, to answer this question we need two equations: (1) one to express the area (A) of a triangle, and (2) one describing the fact that height (h) and the base (b) lengths are related. Setting up and solving the system of these two equations for base leads to a quadratic equation:

which has two solutions but one is negative, i.e., not applicable. The good solution for base is
.
Since we know the height is 8 ft less than the base, the height must be 9.71ft