Question:
Note Use $\pi=\frac{22}{7}$, unless stated otherwise.
A conical pit of diameter 3.5 m is 12 m deep. What is its capacity in kilolitres?
HINT 1 m3 = 1 kilolitre.
Solution:
Radius of the conical pit, $r=\frac{3.5}{2} \mathrm{~m}$
Depth of the conical pit, h = 12 m
$\therefore$ Capacity of the conical pit $=\frac{1}{3} \pi r^{2} h=\frac{1}{3} \times \frac{22}{7} \times\left(\frac{3.5}{2}\right)^{2} \times 12=38.5 \mathrm{~m}^{3}=38.5 \mathrm{~kL} \quad\left(1 \mathrm{~m}^{3}=1\right.$ kilolitre $)$
Thus, the capacity of the conical pit is 38.5 kL.