The surface area of a sphere of radius r is 4 π2
π
r
2
Half of this is 2π2
2
π
r
2
Which is the area of hemisphere
The area of a circle of radius r is π2
thus if the hemisphere is meant to include the base then the surface area is
2π2+π2=3π2
2
π
r
2
+
π
r
2
=
3
π
r
2
Hence in this case 3π2=3×π×102=942.477796..
