WAEC 2022 · Paper 1 · Q42

Find the volume of a cone of radius $3.5\text{ cm}$ and vertical height $12\text{ cm}$ . $\left[\text{Take }\pi = \frac{22}{7}\right]$

Worked solution (try it first)

Volume of a cone: $\frac13\pi r^2h$ , and $3.5^2 = 12.25$ .
$\frac13 \times \frac{22}{7} \times 12.25 \times 12 = \frac{22}{7} \times 49$
$= 154\text{ cm}^3$ , option D.