# Mensuration-7

### From Homeworkwiki

**Find the volume and surface area of a sphere whose diameter is 21 cm.**

**Solution:** The radius of the sphere = 21/2 = 10.5 cm

Hence, the volume of the sphere = 4/3 x π r^{3}

= 4/3 x 22/7 x (10.3)^{3} cu. cm

= 4851 cu. cm

Surface area of the sphere = 4 π r^{2}

= 4 x 22/7 x 10.5 sq. cm

= 1386 sq. cm