Question

Question 7
Find the volume of a sphere whose surface area is $154c{m}^2$.
$[Assume\pi =\frac{22}{7}]$

Answer 1

Let the radius of the sphere be r.
Surface area of the sphere $=154c{m}^2\Rightarrow 4\pi r^2=154c{m}^2$
$\Rightarrow r^2=\left(\frac{154\times 7}{4\times 22}\right)c{m}^2$
$\Rightarrow r=\left(\frac{7}{2}\right)cm=3.5cm$
$Volumeofsphere=\frac{4}{3}\pi r^3$
$=[\frac{4}{3}\times \frac{22}{7}\times (3.5{)}^3]c{m}^3$
$=179\frac{2}{3}c{m}^3$