Question

The volume of cylinder is $3960{\mathrm{cm}}^3$. Its curved surface area is $1320{\mathrm{cm}}^2$, then radius of the base of cylinder is___

Answer 1

Answer: 6

Vol. of cylinder $=3960$
Surface area $=2\pi rh$
$2\pi rh=1320$
$rh=\frac{1320\times 7}{22\times 2}$
$rh=210$
$\mathrm{Vol}=3960$
$\pi r^{2}h=3960$
$\pi r(rh)=3960$
$\pi r(210)=3960$
$r=\frac{3960\times 7}{22\times 210}=6\mathrm{cm}$