Question

The radius of a cone is 5 cm and vertical height is 12 cm.Find the area of the curved surface.

Answer 1

Radius of the base of a cone=5 cm

Vertical height (h) = 12 cm

$\therefore Slantheight\left(l\right)=\sqrt{r^2+h^2}=\sqrt{(5{)}^2+(12{)}^2}cm=\sqrt{25+144}=\sqrt{169}=\sqrt{(13{)}^2}cm=13cm\therefore Curvedsurfacearea=\pi rl=\frac{22}{7}\times 5\times 13=\frac{1430}{7}c{m}^2=204.28c{m}^2$