The area of the base of a cylinder is $20 \, cm^{2}$ and its height is $5 \, cm$. Then,its volume is $\ldots \ldots \ldots \, cm^{3}$.

$A$ mason constructs a wall of dimensions $270 \,cm \times 300 \,cm \times 350 \,cm$ with bricks each of size $22.5 \,cm \times 11.25 \,cm \times 8.75 \,cm$. If $\frac{1}{8}$ of the total volume of the wall is occupied by mortar,find the number of bricks used to construct the wall.

$A$ building is in the form of a cylinder surmounted by a hemispherical dome (see figure). The base diameter of the dome is equal to $\frac{2}{3}$ of the total height of the building. Find the height of the building,if it contains $67 \frac{1}{21} \, m^3$ of air. (in $m$)

The base of a cone with radius $7\, cm$ and height $24\, cm$ is hemispherical. Find the cost of painting its surface at the rate of ₹ $2/cm^2$. (in ₹)

The $TSA$ (Total Surface Area) of a $5$-rupee coin is given by the formula $\ldots \ldots \ldots . .$

The ratio of diameters of two cones is $2:3$ and the ratio of their heights is $9:4$. Then,the ratio of their volumes is: