Question

Find the curved surface area of a frustum of cone. The slant height is 12 m, top and bottom radius is 2 and 3 m respectively. (Use $\pi$ = 3.14)

• A. 178.4 m${}^2$
• B. 188.4 m${}^2$
• C. 186.4 m${}^2$
• D. 198.4 m${}^2$

Answer 1

The correct option is B 188.4 m${}^2$

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

$=3.14\times 12\ast (2+3)$

$=3.14\times 12\ast \left(5\right)$

$=3.14\times 60$

$=188.4m^2$