First step is to know the equations for circumference and area of a circle.
[tex]\begin{gathered} P=2\pi r \\ A=\pi\cdot r^2 \end{gathered}[/tex]
Given the circumference, it is possible to find the radius by clearing it from the equation.
[tex]\begin{gathered} 30\pi=2\pi r \\ \frac{30\pi}{2\pi}=r \\ 15=r \end{gathered}[/tex]
Then find the area using the equation and the estimated radius
[tex]\begin{gathered} A=\pi\cdot15^2 \\ A=225\pi \end{gathered}[/tex]
The answer is 225 pi square inches
