Find the amount of water displaced by a solid spherical ball of diameter $4.2 \, cm$,when it is completely immersed in water. (in $, cm^3$)

The radius of the base of a cone is $7 \, cm$ and its height is $30 \, cm$. Find the volume of a cone (in $cm^3$).

The length, breadth, and height of a cuboid are $30 \, cm$, $20 \, cm$, and $15 \, cm$ respectively. Its volume is $\ldots \ldots \ldots \, cm^3$.

The radii of two cylinders are in the ratio of $2:3$ and their heights are in the ratio of $5:3$. The ratio of their volumes is

The length,breadth,and height of a hall are $7\, m$,$5\, m$,and $4\, m$ respectively. It has two doors measuring $3\, m \times 2\, m$ each and four windows measuring $2\, m \times 1\, m$ each. Find the cost of whitewashing all the four walls and the ceiling of the hall at the rate of ₹$200$ per $m^2$.

Find the curved surface area of a cylinder whose height is $35 \, cm$ and radius of the base is $15 \, cm$. (in $cm^2$)