SOLUTION
The diagram below will help us answer the question
From the diagram above, Area of the shaded region is
[tex]Area\text{ of shaded region = Area of rectangle - Area of semi-circle }[/tex]
From the diagram, the rectangle has a width of 9 ft, which is also the radius of the semi-circle. So the length of the rectangle is also equal to the diameter of the semi-circle, which is
[tex]\begin{gathered} 2\times9=18ft \\ So\text{ length of rectangle = 18 ft} \\ width\text{ = 9 ft } \\ Area\text{ of rectangle = length }\times\text{ width } \\ =18\times9 \\ =162\text{ ft}^2 \end{gathered}[/tex]
Area of a semi-circle is given as
[tex]\begin{gathered} Area\text{ of semi-circle = }\frac{1}{2}\times\pi r^2 \\ =\frac{1}{2}\times3.14\times9^2 \\ =\frac{1}{2}\times3.14\times81 \\ =127.17 \end{gathered}[/tex]
Area of shaded region becomes
[tex]\begin{gathered} 162-127.17 \\ =34.83\text{ ft}^2 \end{gathered}[/tex]
Hence the answer is 34.83 square-feet
