Question

The total surface area of frustum cone is 270 $i{n}^2$. The radius of a top cone is 2 and the bottom cone is 2 in. Find the curved surface area of a frustum cone. (Use $\pi$ = 3.14).

• A. 234.88 in
• B. 244.88 in
• C. 254.88 in
• D. 264.88 in

Answer 1

The correct option is B 244.88 in

Total surface area = $\pi (R+r)s+\pi R^2+\pi r^2$

Curved surface area = $\pi$(R + r)s

Therefore, 270 = Curved surface area $+\pi (2^2+2^2)$

270 = Curved surface area $+3.14(4+4)$

270 - 25.12 = Curved surface area

Curved surface area = 244.88 in