Question

From a solid cylinder of height $14cm$ and base diameter $7cm$, two equal conical holes each of radius $2.1cm$ and height $4cm$ are hollowed out. Find the volume of the remaining solid.

Answer 1

Volume of cylinder $=\pi r^{2}h=\pi \times {\left(\frac{7}{2}\right)}^2\times 14$

$=539c{m}^3$

Volume of $2$ conical holes $=2\times \frac{1}{3}\pi \left(2.1{)}^2\right(4)$

$=36.96c{m}^3$

Remaining volume $=539-36.96$

$=502.04c{m}^3$.