The area of circle is
[tex] A_{\text{circle}}=\pi r^2. [/tex]
Then the area of semicircular region is
[tex] A_{\text{semicircular region}}=\dfrac{1}{2} \pi r^2. [/tex]
If r=3 m, you have
[tex] A_{\text{semicircular region}}=\dfrac{1}{2} \pi \cdot 3^2=\dfrac{9\pi}{2}=4.5\pi \approx 14.13 [/tex] sq. m.
Answer: [tex] A_{\text{semicircular region}}=4.5\pi \approx 14.13 [/tex] sq. m.
