The volume of a cone with radius $5 \, cm$ and height $21 \, cm$ is $\ldots \ldots \ldots \, cm^{3}$.

$A$ cone of height $24\, cm$ and radius of base $6\, cm$ is made up of modelling clay. $A$ child reshapes it in the form of a sphere. Find the radius of the sphere (in $cm$).

An ice cream cone full of ice cream has a radius of $5 \, cm$ and a total height of $10 \, cm$ as shown in the figure. Calculate the volume of the ice cream,provided that its $\frac{1}{6}$ part is left unfilled with ice cream. (in $cm^{3}$)

How many balls with diameter $0.5\, cm$ can be produced by melting a metallic cylinder with radius $2\, cm$ and height $8\, cm$?

$A$ metallic sphere with radius $6 \, cm$ is melted and recast into a wire of radius $0.4 \, cm$. Find the length of the wire in metres.

Volume of a cone $= \dots$