The radii of two circular faces of the frustum of a cone of height 10.5 cm are 5 cm and 3 cm respectively. What is its volume in cm3 ( = 227 )?

Answer: Option B

Solution

Answer: Option B

Solution:

$$\begin{array}{rl}& \text{V}=\frac{1}{3}\pi \left(R^2+r^2+Rr\right)h\\ & \text{V}=\frac{1}{3}\times \frac{22}{7}\left(25+9+15\right)\times 10.5\\ & \text{V}=11\times 49\\ & \text{V}=539\text{ c}{\text{m}}^2\end{array}$$