Question

Find the surface area of sphere whose radius is \( 2.1 cm \).

Answer 1

jyothi4059, hello 

The formula for the surface area of a sphere is: \(A = {4 \pi r^2}\)

Substituting in 2.1cm for r we get: 17.64pi cm² or approximately 55.44cm²

Answer 2

Radius of sphere, r = 2.1 cm

Volume of sphere = \(\frac {4}{3} \pi r ^3\)

\(=\frac {4}{3} \times \frac {22}{7} \times (2.1)^3 =\) 38.8 cm³

Surface area of sphere = 4πr²

\(=4 \times \frac {22}{7} \times 2.1 \times 2.1 =\) 55.44 cm²