Find the surface area of a sphere of radius $50\, cm$ $(\pi = 3.14)$ (in $cm^2$).

Write True or False and justify your answer in each of the following: If the length of the diagonal of a cube is $6 \sqrt{3} \, \text{cm}$,then the length of the edge of the cube is $3 \, \text{cm}$.

The curved surface area of a cylinder is $1320 \, cm^2$. If its height is $30 \, cm$,find its diameter (in $cm$).

$A$ storage tank is in the form of a cube. When it is full of water, the volume of water is $15.625 \, m^3$. If the present depth of water is $1.3 \, m$, find the volume of water already used from the tank (in $m^3$).

The curved surface area of a cylinder is $550 \, cm^2$. If its height is $50 \, cm$,find its diameter in $cm$.

Write True or False and justify your answer.
An edge of a cube measures $r \, cm$. If the largest possible right circular cone is cut out of this cube,then the volume of the cone (in $cm^3$) is $\frac{1}{6} \pi r^3$.