Question

The radius of a sphere is 'r' centimeters it is divided into two equal parts . Find the whole surface of two parts.

Answer 1

Radius of a sphere = r cm
If the sphere is divided into two equal parts, then the resulting parts are hemispheres with radius r cm.
Total surface area of each hemisphere $=3\pi r^2$
Total surface area of both parts $=2\times 3\pi r^2=6\pi r^2$
Hence, the whole surface areas of two parts is $6\pi r^2$