The height of a cone is $15 \, cm$. If its volume is $1570 \, cm^3$,find the radius of the base. (Use $\pi = 3.14$) (in $, cm$)

$A$ conical tent is $10 \, m$ high and the radius of its base is $24 \, m$. Find the slant height of the tent. (in $, m$)

The hollow sphere,in which the circus motorcyclist performs his stunts,has a diameter of $7 \,m$. Find the area available to the motorcyclist for riding. (in $,m^2$)

$A$ wall of length $10\, m$ was to be built across an open ground. The height of the wall is $4\, m$ and thickness of the wall is $24\, cm$. If this wall is to be built up with bricks whose dimensions are $24\, cm \times 12\, cm \times 8\, cm$,how many bricks would be required?

Find the amount of water displaced by a solid spherical ball of diameter $0.21 \, m$. (in $, m^3$)

The circumference of the base of a cylindrical vessel is $132 \,cm$ and its height is $25 \,cm$. How many litres of water can it hold (in $,l$)? $(1000 \,cm^3 = 1 \,l)$ Assume $\pi = \frac{22}{7}$.