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 $g$).

The diameter of a solid hemisphere is $21 \, cm$,then its volume is $\ldots \ldots \ldots \, cm^3$.

The circumference of the base of a cylindrical vessel is $440\, cm$ and its height is $80\, cm$. Find the volume of the cylinder in $m^3$.

$1$ hectare $= \ldots \ldots \text{ } m^{2}$

Metal spheres,each of radius $2 \, cm$,are packed into a rectangular box of internal dimensions $16 \, cm \times 8 \, cm \times 8 \, cm$. When $16$ spheres are packed,the box is filled with preservative liquid. Find the volume of this liquid. Give your answer to the nearest integer. [Use $\pi = 3.14$] (in $cm^3$)

$A$ shopkeeper has one spherical laddoo of radius $5 \, cm$. With the same amount of material,how many laddoos of radius $2.5 \, cm$ can be made?