The radius of the base of a cone is 5 cm and ir=ts heights is 12 cm . Its curved surface area is

Options

A. `60pi cm^2`
B. `65pi cm^2`
C. `30pi cm^2`
D. none of these

Answer

B

Explanation

Here r = 5 cm and h = 12 cm.
`:.l^2=(r^2+h^2)=(5)^2=912)^2=169rArr l=sqrt169=13 cm`.
Curved surface area `=pirl =(pixx5xx13)cm^2=(65pi)cm^2`.