Question

Radii of the top and the base of a frustum of

a cone are 5 cm and 2 cm respectively. Its

height is 9 cm. Find its volume. (π = 3.14)

Answer 1

Since, the volume of a frustum =
$\frac{1}{3} \pi \: h \: ( {r1}^{2} + {r}^{2} + r1 \times r2)$
=1/3 * 3.14 * 9 (
${5}^{2} + {2}^{2} \times 5 \times 2)$
=1 * 3.14 * 3(25 + 4 + 10)
=31.4 * 3 (39)
=3.14 * 117
=367.71 cm