The radius of a sphere is $2r$,then its volume will be

For a given cylinder,the radius of the base is $28 \, cm$ and its height is $90 \, cm$. Find the curved surface area and the total surface area of the cylinder.

Write True or False and justify your answer: The volume of a sphere is equal to two-thirds of the volume of a cylinder whose height and diameter are equal to the diameter of the sphere.

The diameter of a solid sphere is $14 \, cm$. Find its surface area in $cm^2$.

How many square metres of canvas is required for a conical tent whose height is $3.5 \, m$ and the radius of the base is $12 \, m$ (in $, m^{2}$)?

The volume of a cube is $3375\, cm^{3}$. Find its edge and total surface area.