We find its area as follows:
[tex]A=\frac{1}{2}\pi r^2[/tex][This is the equation for the area of a circle divided by 2] Now, we replace the radius:
[tex]A=\frac{1}{2}\pi(9)^2\Rightarrow A=\frac{81}{2}\pi\Rightarrow A\approx127.23[/tex]So, the area of the semi-circle is approximately 127.23 squared feet.
