(Q7)Find the volume and surface area of a sphere of radius 2.1 cm (π =
22
7
)

2.1cm

Radius of sphere(r) = cm

Surface area of sphere = 4πr2

= 4 ×
22
7
× ( 2) = 4 ×
22
7
×
10
×
10
=
25
= cm2
Volume of sphere =
4
3
πr3 =
4
3
×
22
7
× ( )3
=
4
3
×
22
7
× × × = cm3