Question

What is the area of a semicircle of radius 4r?

Answer 1

Dear student,
$$\begin{gathered} Areaofsemicircle=\frac{{\mathrm{\pi r}}^2}{2} \\ puttingradius=4r \\ Areaofsemicircle=\frac{\pi {\left(4r\right)}^2}{2}=\frac{\mathrm{\pi }\times 4\mathrm{r}\times 4\mathrm{r}}{2}=8{\mathrm{\pi r}}^2 \end{gathered}$$
Regards