The radius and volume of a cylinder are $3.5\,cm$ and $2310\,cm^3$ respectively. Find its height in $cm$.

$A$ well,$20 \, m$ deep,is $7 \, m$ in radius. Find the cost of cementing the inner curved surface at the rate of ₹ $15$ per $m^2$. (in ₹)

The surface area of a sphere is $7850 \, cm^2$. Find its radius in $cm$. (Use $\pi = 3.14$)

The radii of three out of four spheres are $33 \, cm$,$44 \, cm$,and $48 \, cm$ respectively. If the surface area of the fourth sphere is equal to the sum of the surface areas of the first three spheres,find the radius of the fourth sphere (in $cm$).

The radius and slant height of a conical vessel are $21 \,cm$ and $29 \,cm$ respectively. What is its capacity in litres?

The dome of a building is in the form of a hemisphere. Its radius is $4.2 \, m$. Find the cost of painting it at the rate of ₹ $18$ per $m^2$. (in ₹)