Question

If a cone has a radius of 5 cm and height of 12 cm, then match the following.

• A. 13 cm
• B. $90\pi c{m}^2$
• C. $65\pi c{m}^2$

Answer 1

Slant height of the cone,$l=\sqrt{r^2+h^2}$
$=\sqrt{5^2+{12}^2}$
$=\sqrt{{13}^2}$
$=13cm$

TSA of the cone $=\pi r(r+l)$
$=\pi \times 5(5+13)$
$=5\pi \times 18$
$=90\pi c{m}^2$

CSA of the cone $=\pi rl$
$=\pi \times 5\times 13=65\pi c{m}^2$