The volume of a solid cylinder is $4620 \, cm^{3}$ and its radius is $7 \, cm$. Find its height in $cm$.

The volumes of two spheres are in the ratio $64: 27$. Find the ratio of their surface areas.

$A$ small village,having a population of $5000$,requires $75$ litres of water per head per day. The village has an overhead tank of measurement $40 \, m \times 25 \, m \times 15 \, m$. For how many days will the water of this tank last?

Find the volume of a sphere whose surface area is $1256 \, cm^{2}$. (Use $\pi = 3.14$)

The radius of a sphere is decreased by $20 \% .$ By what per cent does its curved surface area decrease (in $\%$)?

The water for a factory is stored in a hemispherical tank whose internal diameter is $14\, m$. The tank contains $50$ kilolitres of water. Water is pumped into the tank to fill it to its capacity. Calculate the volume of water pumped into the tank. (in $, m^{3}$)