Question

A frustum of a right circular cone is of height $16$ cm with radii of its ends as $8$ cm and $20$ cm. What is the volume of the frustum?

• A. $3328\pi c{m}^3$
• B. $3228\pi c{m}^3$
• C. $3240\pi c{m}^3$
• D. $3340\pi c{m}^3$

Answer 1

The correct option is A $3328\pi c{m}^3$

Volume of a frustum of a cone $=\frac{1}{3}\pi h(R^2+r^2+Rr)$, where $h$ is the height and $R$ and $r$ are the radii of the lower and upper ends of a frustum of a cone.

Hence, volume of the frustum of the cone $=\frac{1}{3}\pi \times 16({20}^2+8^2+20\times 8)$

$=3328\pi {cm}^2$