Question

The volume of a right circular cone is $9856c{m}^3$. If the diameter of the base is $28cm$. find
slant height of the cone

Answer 1

Volume of cone $=\frac{1}{3}\pi r^{2}h$

$\Rightarrow 9856=\frac{\pi }{6}(14{)}^{2}h$

$\Rightarrow h=\frac{9856\times 3\times 7}{14\times 14\times 22}=48$cm

By Pythagoras theorem, $l^2=h^2+r^2$

$\Rightarrow l=\sqrt{{48}^2+{14}^2}=\sqrt{2304+196}=\sqrt{2500}=50$cm.