Question

Volume of cone is $12\pi$ if height is $3cm$ find the $CSA$ of cone.

Answer 1

Volume of cone is

$\frac{1}{3}\pi r^{2}h=12\pi r^2=12r=\sqrt{1}2$

$l^2=r^2+h^2{l}^2=12+9l^2=21l=\sqrt{21}$

CSA of cone is

$\pi rl$

$\pi \sqrt{12}\sqrt{21}=6\sqrt{7}\pi$