The capacity of a closed cylindrical vessel of height $1 \mathrm{m}$ is $15.4$ litres. If $A {\mathrm{cm}}^2$ of metal sheet would be needed to make it, then find the value of $A$. (Assume $\mathrm{\pi }=\frac{22}{7}$)

A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is $7 \mathrm{m}\mathrm{m}$ and the diameter of the graphite is $1 \mathrm{m}\mathrm{m}.$ If the length of the pencil is $14 \mathrm{c}\mathrm{m},$ find the volume of the wood and that of the graphite. (Assume $\mathrm{\pi }=\frac{22}{7}$)

A patient in a hospital is given soup daily in a cylindrical bowl of diameter $7 \mathrm{c}\mathrm{m}.$ If the bowl is filled with soup to a height of $4 \mathrm{c}\mathrm{m}$ and $A \mathrm{litres}$ of soup the hospital has to prepare daily to serve $250$ patients, then find the value of $A$. (Assume $\mathrm{\pi }=\frac{22}{7}$)

Take, $\mathrm{\pi }=\frac{22}{7}$.
If the volume of a right circular cone with radius $3.5 \mathrm{c}\mathrm{m},$ height $12 \mathrm{c}\mathrm{m}$ is $k {\mathrm{cm}}^3$, then find the value of $k$.