The total surface area of a cube is $864 \, cm^2$. Then its edge is $\ldots \ldots \ldots \, cm$.

$A$ hemispherical bowl of radius $18\, cm$ is completely filled with medicine. This medicine is to be filled in cylindrical bottles of radius $2\, cm$ and height $4\, cm$. How many bottles are required to empty the bowl?

The radius of a sphere is increased by $10 \%$. Prove that the volume will be increased by $33.1 \%$ approximately.

The length,breadth,and height of a cuboidal box are $30 \, cm$,$20 \, cm$,and $8 \, cm$ respectively. Find the lateral surface area of the cuboidal box (in $cm^2$).

State whether the following statement is true or false:
The lateral surface area of a cube with an edge length of $5 \, cm$ is $150 \, cm^2$.

The diameter of a solid hemisphere is $42\, cm.$ Find the curved surface area of a hemisphere (in $cm^2$).