Question

The curved surface of a cylindrical pillar is $264$ ${\text{cm}}^2$ and its volume is $924$ ${\text{cm}}^3$. Find the diameter.

Answer 1

$2\pi rh=264$ and $\pi r^{2}h=924$
$\therefore \frac{\pi r^{2}h}{2\pi rh}=\frac{924}{264}$
or $\frac{r}{2}=\frac{7}{2}$ i.e
$r=7$ or $2r=14m.$