Question

The slant height of a cone is 30 in, top and bottom diameter is 3.5 and 1.6 in respectively. Find the curved surface area of a frustum of cone. (Use $\pi$ = 3.14)

• A. 950.84 in${}^2$
• B. 940.84 in${}^2$
• C. 960.84 in${}^2$
• D. 930.84 in${}^2$

Answer 1

Answer: (C)

960.84 in${}^2$

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

Diameter = radius/2

Radius, R = 7 in, r = 3.2 in

$=3.14\times 30(7+3.2)$

$=3.14\times 30\left(10.2\right)$

$=3.14\times 306$

$=960.84i{n}^2$