The radii of two circular faces of the frustum of a cone of height 21 cm are 3 cm and 2 cm respectively. What is the volume of the frustum of the cone in cm³ $$\left( {\pi = \frac{{22}}{7}} \right)?$$

Solution (By Examveda Team)

$$\eqalign{ & {\text{Volume}} = \frac{1}{3}\pi \left( {{R^2} + {r^2} + Rr} \right)h \cr & = \frac{1}{3} \times \frac{{22}}{7} \times \left( {9 + 4 + 6} \right) \times 21 \cr & = 22 \times 19 \cr & = 418{\text{ c}}{{\text{m}}^3} \cr} $$