The volume of a right circular cone is $9856 \, cm^3$. If the diameter of the base is $28 \, cm$,find the slant height of the cone. (in $, cm$)

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

$A$ right triangle $ABC$ with sides $5 \, cm, 12 \, cm$ and $13 \, cm$ is revolved about the side $12 \, cm$. Find the volume of the solid so obtained. Also,find the volume of the solid obtained when the same triangle is revolved about the side $5 \, cm$. Finally,find the ratio of the volumes of the two solids.

The diameter of a metallic ball is $4.2\, cm$. What is the mass of the ball,if the density of the metal is $8.9\, g/cm^3$ (in $, g$)?

$A$ heap of wheat is in the form of a cone whose diameter is $10.5\, m$ and height is $3\, m$. Find its volume. The heap is to be covered by canvas to protect it from rain. Find the area of the canvas required. (in $, m^{2}$)

Find the curved surface area of a right circular cone whose slant height is $10\, cm$ and base radius is $7\, cm$. (in $, cm^{2}$)