Question:
A spherical cannonball 28 cm in diameter is melted and cast into a right circular cone would, whose base is 35 cm in diameter. Find the height of the cone.
Solution:
Radius of the spherical cannonball, R = 14 cm
Radius of the base of the cone, r = 17.5 cm
Let h cm be the height of the cone.
Now, volume of the sphere = volume of the cone
$\Rightarrow \frac{4}{3} \pi R^{3}=\frac{1}{3} \pi r^{2} h$
$\Rightarrow 4 \times 14^{3}=(17.5)^{2} \times h$
$\Rightarrow h=\frac{4 \times 14 \times 14 \times 14}{17.5 \times 17.5}=35.84 \mathrm{~cm}$
∴ The height of the cone is 35.84 cm.