circumference = 24 miles
[tex]\begin{gathered} \text{circumference of a circle=2}\pi r \\ 24=2\pi r \\ r=\frac{24}{2\pi} \\ r=\frac{12}{\pi} \end{gathered}[/tex]Therefore, area will be
[tex]\begin{gathered} \text{area}=\pi r^2 \\ \text{area}=\pi\times(\frac{12}{\pi})^2 \\ \text{area}=\frac{144}{\pi} \\ \text{area}=\frac{144}{3.14159} \\ \text{area}=45.836662327 \\ \text{area}=46miles^2 \end{gathered}[/tex]