Question

The height of a cone is $16cm$ and its base radius is $12cm(\pi =3.14)$
Find $\left(i\right)$ its slant height, $\left(ii\right)$ its curved surface area.

Answer 1

Given height of cone $=16$ cm

radius of base $=12$ cm

(1) slant height $l=\sqrt{r^2+h^2}$

$l=\sqrt{(12{)}^2+(16{)}^2}$

$l=\sqrt{144+256}$

$l=\sqrt{400}$

$l=20$ cm

$\therefore$ slant height of cone is $20$ cm

(2) CSA of cone = $\pi rl$

$=3.14\times 12\times 20$

$=240\times 3.14$

CSA of cone = $753.6c{m}^2$