Question

Find the surface area of a sphere of radius 10.5 cm.

${\displaystyle [\text{Assume}\pi =\frac{22}{7}]}$

Answer 1

Radius (r) of sphere = 10.5 cm

Surface area of sphere = 4πr²

= ${\displaystyle [4\times \frac{22}{7}\times {\left(10.5\right)}^2]c{m}^2}$

= ${\displaystyle (4\times \frac{22}{7}\times 10.5\times 10.5)c{m}^2}$

= (88 × 1.5 × 10.5) cm²

= 1386 cm²

Therefore, the surface area of a sphere having a radius of 10.5 cm is 1386 cm².