Question

Find the volume of the sphere whose surface area is $9856$ ${\text{cm}}^2$.

Answer 1

Surface area of sphere $=4\pi r^2$

Thus $9856=4\times \frac{22}{7}\times r^2$

$\Rightarrow r^2=\frac{9856\times 7}{4\times 22}$

$\Rightarrow r^2=784$

So, $r=28$ cm.

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

$=\frac{4}{3}\times \frac{22}{7}\times 28\times 28\times 28$

$=91989.33{\text{cm}}^3$