A spherical cannon ball, 28 cm in diameter is melted and recast into a right circular conical mould, the base of which is 35 cm in diameter. Find the height of the cone, correct to one place of decimal.
Let h be the height of cone. Then
1/3π(35/2)^{2} h = 4/3π(14)^{3}
(Because the volume of conical mould is the same as that of the spherical cannon ball)
⇒ h = 4 × 14 × 14 × 14 × 2 × 2/35 × 35
= 896/25 = 35.84 cm.