We are asked to determine the area of a circle with a diameter of 80 feet. To do that, let's remember the formula for the area of a circle:
[tex]A=\frac{\pi D^2}{4}[/tex]Replacing the value of the diameter
[tex]A=\frac{\pi(80ft)^2}{4}[/tex]Solving the operation:
[tex]A=\frac{\pi(6400ft^2)}{4}[/tex][tex]A=\pi(1600ft^2)\approx5026.55ft^2[/tex]