The area of a circle (A) is computed as follows:
[tex]A=\pi\cdot\frac{D^2}{4}[/tex]
where D is the diameter of the circle.
From the picture, D = 81 ft. Using 22/7 as an approximation of π, we get:
[tex]\begin{gathered} A=\frac{22}{7}\cdot\frac{81^2}{4} \\ A=\frac{22\cdot6561}{28} \\ A=5155.1ft^2 \end{gathered}[/tex]
