The volume of a $1-$ rupee coin is given by the formula $\ldots \ldots \ldots . . .$

$A$ cylindrical tank with radius $8.4 \,cm$ is closed at one end by a hemisphere. If the total height of the tank is $52.8 \,cm$,how many litres of petrol can it contain (in $.088$)? (in $litres$)

How many balls of radius $0.5\, cm$ can be produced by melting a metallic cylinder with radius $4\, cm$ and height $3\, cm$?

$A$ metallic cylinder with diameter $1 \, cm$ and height $4 \, cm$ is melted and recast to produce balls of radius $\frac{1}{8} \, cm$. Find the number of balls produced.

Find the number of metallic circular discs with $1.5\, cm$ base diameter and height $0.2\, cm$ that must be melted to form a right circular cylinder of height $10\, cm$ and diameter $4.5\, cm$.

The area of the base of a cone is $60 \, cm^{2}$ and its height is $15 \, cm$. Then,the volume of the cone is $\ldots \ldots \ldots \, cm^{3}$.