Given that the are of the great circle is 227 km^2.
The hemisphere is the half of a sphere, the surfsce area wiill be:
SA= (1/2)surface area of the sphere+ base area
the curve surface area will be:
[tex]\frac{1}{2}*4\pi r^2[/tex]
and we know that the base area is:
[tex]\begin{gathered} BA=\pi r^2=227km^2 \\ r^2=\frac{227km^2}{\pi} \\ r=\sqrt[\placeholder{⬚}]{\frac{227}{\pi}}=8.5km \end{gathered}[/tex]
substituting:
[tex]\begin{gathered} SA=\frac{1}{2}(4\pi r^2)+227km^2 \\ SA=2\pi(8.5km)^2+227km^2=680.96km^2 \end{gathered}[/tex]
The surface area is: 680.96 square kilometers.
