Lateral surface area of a cube $= \ldots \ldots \ldots$

$A$ 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 volumes of two spheres are in the ratio $64: 27$. Find the ratio of their surface areas.

$1 \, m^{2} = \ldots \ldots \, cm^{2}$

The curved surface area of a cylinder is $3960 \, cm^{2}$ and its volume is $41580 \, cm^{3}$. Find the radius and height of the cylinder.

The radius and the slant height of a cone are in the ratio $4: 7$. The ratio of its total surface area to its curved surface area is $\ldots \ldots \ldots$