169π ft² or approximately 530.92 ft²
1) Considering a pool shaped like a circle:
2) Since the Diameters is twice the radius, then we can write:
[tex]\begin{gathered} R=13ft \\ A=\pi(13)^2 \\ A=169\pi ft^2\text{ or }\approx\text{530}.92ft^2 \end{gathered}[/tex]3) So the are of the pool is 169π ft² or approximately 530.92 ft²