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 $$\left( {\pi = \frac{{22}}{7}} \right)?$$

Solution (By Examveda Team)

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