Question

The radius of a cone is $5cm$ and height is $12cm$. Find the slant height of cone.

Answer 1

If the slant height of a cone is $l$ and it's height and radius are $h$ and $r$ respectively.

Then, $l^2=h^2+r^2$

In this case, $l^2={12}^2+5^2=169\Rightarrow l=\sqrt{169}=13cm$