If a marble of radius $2.1 \, cm$ is put into a cylindrical cup full of water of radius $5 \, cm$ and height $6 \, cm$,then how much water flows out of the cylindrical cup? (in $cm^3$)

The volume of a cone is equal to:

$A$ spherical glass vessel has a cylindrical neck $8 \, cm$ long and $2 \, cm$ in diameter. The diameter of the spherical part is $8.5 \, cm$. By measuring the amount of water it holds,a child finds its volume to be $345 \, cm^{3}$. Check whether she is correct,taking the above as the inside measurements,and $\pi = 3.14$. (in $, cm^{3}$)

$A$ hollow cube of internal edge $22 \, cm$ is filled with spherical marbles of diameter $0.5 \, cm$. It is assumed that $\frac{1}{8}$ of the space of the cube remains unfilled. The number of marbles that the cube can accommodate is:

Derive the formula for the volume of the frustum of a cone.

$A$ $20\, m$ deep well with diameter $7\, m$ is dug and the earth from digging is evenly spread out to form a platform $22\, m$ by $14\, m$. Find the height of the platform. (in $m$) [Take $\pi=\frac{22}{7}$]