Question

The radius of the base of a cone is 5 cm and its height is 12 cm. Its curved surface area is

Options

• 60π cm²

• 65π cm²

• 30π cm²

• None of these

Answer 1

65π cm²

Given: r = 5 cm, h = 12 cm

Slant height of the cone,` l = sqrt("r"^2 + "h"^2)`

`= sqrt((5)^2 + (12)^2)`

`= sqrt(25 + 144)`

`= sqrt(169)`

= 13 cm

Hence, the curved surface area of the cone` =pi"rl" `

`= (pixx5xx13)  "cm"^2`

= 65 π cm²