Question

The radii of ends of a frustum are $14\text{cm}$ and $6\text{cm}$ respectively and its height is $6\text{cm}$. Find its volume.

Answer 1

Here, $R=14\text{cm},r=6\text{cm},h=6\text{cm}$

$\begin{array}{cc}V& =\frac{1}{3}\pi h\left(r^2+Rr+R^2\right)\\ & =\frac{1}{3}\times \frac{22}{7}\times 6\left[6^2+\left(14\right)\left(6\right)+{\left(14\right)}^2\right]\\ & =\frac{22}{7}\times 2\left[36+84+196\right]\\ & =\frac{22}{7}\times 632\\ & =1986.2{\text{cm}}^3\end{array}$