Question

A solid wooden toy is in the shape of a right circular cone mounted on a hemisphere. If the radius of the hemisphere is 4.2 cm and the total height of the toy is 10.2 cm, find the volume of the wooden toy (nearly).

Answer 1

Height of cone $=10.2-4.2=6cm$

$\therefore$ Volume of toy $=$ Vol. of cone $+$ Vol. of hemisphere

$=\frac{1}{3}\pi r^{2}h+\frac{2}{3}\pi r^3=\frac{1}{3}\pi r^2(h+2r)$

$=\frac{1}{3}\times \frac{22}{7}\times 4.2\times 4.2(6+2\times 4.2)$

$=22\times 0.2\times 1.2\times 4.2\times 14.4=266.112{cm}^3\approx 266{cm}^3$