The length,breadth,and height of a cuboidal box are $25 \, cm$,$20 \, cm$,and $10 \, cm$ respectively. Find its total surface area in $cm^2$.

$A$ metal sphere of radius $20\, cm$ is melted and then cast into small hemispheres each of radius $5\, cm$. Find the number of hemispheres thus obtained (in balls).

The length,breadth,and height of a metallic cuboid are $10\, cm$,$6\, cm$,and $4\, cm$ respectively. If the density of the metal is $7.8\, g/cm^3$,find the mass of the cuboid (in $g$).

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

$A$ square sheet of paper,$44 \, cm$ long,is rolled along its length to form a cylinder. Find the volume of the cylinder so formed. (in $cm^3$)

Write True or False and justify your answer in each of the following: If the radius of a right circular cone is halved and height is doubled,the volume will remain unchanged.