The diameter of an Indian 2 rupee coin is 26 mm and thickness is 1 mm.

The area of the coin to be polished is sq mm.

(Take $ \pi =\frac{22}{7})$

A right circular cylinder is just enclosed a sphere of radius $r$, then :

The diameter of a cylinder is $14 cm$ and its height is $10 cm$, then find the curved surface of the cylinder.

A solid metallic sphere of radius $6 cm$ is melted and made into a solid cylinder of height $32 cm$. Find the curved surface area of the cylinder. (Take $\pi =3.1$)