The curved surface area of a cylinder is $3960\, cm^{2}$. If its radius is $21\, cm$,find its height in $cm$.

$A$ well with $14\, m$ inside diameter is dug $50\, m$ deep. Earth taken out of it is spread all around a rectangular field of length $110\, m$ and width $100\, m$. Find the increase in the height of the field (in $cm$).

The radius of a sphere is $3.5\, cm$. Find the cost of plating gold on its surface at the rate of ₹ $150$ per $cm^{2}$. (in ₹)

Find the volume of a sphere with radius $2.1 \, m$ (in $m^{3}$).

Find the volume of a hemisphere with a diameter of $12 \, cm$. (Use $\pi = 3.14$) (in $cm^3$) (in $.16$)

Find the lateral surface area of a cube with an edge length of $15 \, cm.$ (in $cm^{2}$)