# Frustum of a Right Circular Cone Formula

Frustum of a right circular cone is that portion of right circular cone included between the base and a section parallel to the base not passing through the vertex.

Properties of Frustum of Right Circular Cone

• The altitude of a frustum of a right circular cone is the perpendicular distance between the two bases. It is denoted by h.
• All elements of a frustum of a right circular cone are equal. It is denoted by L.

Formula of Frustum of a Right Circular Cone

$\large A=\pi (R_{1}+R_{2})s$

$\large V=\frac{\pi h}{3}\left(R^{2}+Rr+r^{2}\right)$

### Solved Examples

Question: Find the volume of a frustum of a right circular cone with height 20, lower base radius 34 and top radius 19 ?

Solution:

Given
h = 20
R = 34
r = 19

V = $\frac{\pi h}{3} \left ( R^{2}+ Rr + r^{2} \right)$

V = $\frac{\pi \times 20}{3} \left (34^{2} + 34 \times 19 + 19^{2} \right)$

V = 14420 π

#### Practise This Question

The deficiency of vitamin-C causes