JAMB 2002 · UME · Q9

A bucket is 12 cm in diameter at the top, 8 cm in diameter at the bottom and 4 cm deep. Calculate its volume.

Worked solution (try it first)

The bucket is a frustum with radii $R = 6$ cm and $r = 4$ cm and height 4 cm.
Volume of a frustum: $\frac{\pi h}{3}(R^2 + Rr + r^2) = \frac{4\pi}{3}(36 + 24 + 16)$ .
That is $\frac{4\pi}{3} \times 76 = \frac{304\pi}{3}\text{ cm}^3$ , option B.