Question

Find the surface area of sphere of radius 4.2 cm.

Answer 1

Given: Radius of the sphere (r) = 4.2 cm

Formula: Surface area of a sphere (S) = 4πr²

= `4 xx 22/7 xx (4.2)^2`

= `4 xx 22/7 xx 4.2 xx 4.2`

= 4 × 22 × 0.6 × 4.2

= 88 × 2.52

= 221.76 cm²

The surface area of the sphere is 221.76 cm².