Answer:
592.83 ft^2
Explanation:
First estimate the area of the rectangle:
Area rectangle = Base x Height = 20 * 36 = 720 ft^2
and then subtract from it the area of a semi-circle of radius 18/2 = 9 ft
Using the formula for the semicircle's area:
Semi-circle's area= pi * R^2 / 2 = 3.14 * 9^2 / 2 = 127.17 ft^2
Such gives us:
720 ft^2 - 127.17 ft^2 = 592.83 ft^2