Question

The height and radius of cone 4cm and 3 cm. Fnd the curved surface area of cone.

• A. 14π
• B. 16π
• C. 15π
• D. 12π

Answer 1

The correct option is C

15π

As we revolve a right angle triangle about its height we will get a cone.
$L=\sqrt{(}{h}^2+r^2)=\sqrt{(}{4}^2+3^2)=5cm$
Surface Area of cone = $\pi rl$ = $\pi$ $\times$3 $\times$ 5
= 15$\pi$ ${cm}^2$