Find the volume of a sphere whose radius is $0.63 \, m$. Assume $\pi = \frac{22}{7}$. (in $, m^3$)

Find the radius of a sphere whose surface area is $154 \, cm^2$. (in $, cm$)

The pillars of a temple are cylindrically shaped (see Fig.). If each pillar has a circular base of radius $20\, cm$ and height $10\, m$,how much concrete mixture would be required to build $14$ such pillars (in $, m^3$)?

$A$ cuboidal water tank is $6 \,m$ long,$5 \,m$ wide and $4.5 \,m$ deep. How many litres of water can it hold (in $,l$)? $(1 \,m^3 = 1000 \,l)$

The front compound wall of a house is decorated by wooden spheres of diameter $21 \, cm,$ placed on small supports as shown in the figure. Eight such spheres are used for this purpose,and are to be painted silver. Each support is a cylinder of radius $1.5 \, cm$ and height $7 \, cm$ and is to be painted black. Find the cost of paint required if silver paint costs $25$ paise per $cm^2$ and black paint costs $5$ paise per $cm^2$.

$A$ right triangle $ABC$ with sides $5 \, cm, 12 \, cm$ and $13 \, cm$ is revolved about the side $12 \, cm$. Find the volume of the solid so obtained.