226.08
1) Since the area of the semicircle is half the circle area, then we can write:
[tex]S=\frac{1}{2}\cdot\pi\cdot r^2[/tex]2) So we can plug into that the size of that radius:
[tex]\begin{gathered} S=\frac{1}{2}\cdot\pi\cdot(12)^2 \\ S=\frac{1}{2}\cdot\pi\cdot144 \\ S=72\pi\Rightarrow S=72\times3.14\Rightarrow S=226.08 \end{gathered}[/tex]3) Hence, the area of that semicircle is 226.08 in²