$A$ solid cube of side $12 \, cm$ is cut into eight cubes of equal volume. What will be the side of the new cube? Also,find the ratio between their surface areas.

The inner diameter of a circular well is $3.5\, m$. It is $10\, m$ deep. Find the cost of plastering this curved surface at the rate of $Rs. 40$ per $m^2$.

Find the lateral or curved surface area of a closed cylindrical petrol storage tank that is $4.2\, m$ in diameter and $4.5\, m$ high. $\left[\text{Assume } \pi = \frac{22}{7}\right]$ (in $, m^2$)

Curved surface area of a right circular cylinder is $4.4 \, m^2$. If the radius of the base of the cylinder is $0.7 \, m$,find its height. (Take $\pi = \frac{22}{7}$) (in $, m$)

Find the amount of water displaced by a solid spherical ball of diameter $0.21 \, m$. (in $, m^3$)

Find the volume of a sphere whose surface area is $154 \, cm^2$.