Question

If the volume of a sphere is numerically equal to the surface area of the sphere, then find its radius.

Answer 1

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

Volume of sphere $V=\frac{4}{3}\pi r^2$

We have $A=V$

$\Rightarrow 4\pi r^2=\frac{4}{3}\pi r^3$

$\Rightarrow r=3$ units.