help
posted by Anonymous .
A lot is in the shape of a trapezoid. The sum of the bases is 180 feet. If the area of the lot is 8,100 square feet, what is the distance across the lot, i.e., the altitude of the figure?

since the area is h(a+b)/2,
h (180/2) = 8100
90h = 8100
h = 90