EXERCISE

A cylindrical pillar is $50 \mathrm{c}\mathrm{m}$ in diameter and $3.5 \mathrm{m}$ in height. Find the cost of painting the curved surface of the pillar at the rate of $\mathrm{₹} 12.50$ per ${\mathrm{m}}^2$. [Use, $\pi =\frac{22}{7}$ and write only numerical value without rupee symbol]

Curved surface area of a right circular cylinder is $4.4 {\mathrm{m}}^2$. If the radius of the base of the cylinder is $0.7 \mathrm{m}$ and height is $k \mathrm{m}$, find $k$. $\left(\mathrm{Use} \pi =\frac{22}{7}\right)$

The inner diameter of a circular well is $3.5 \mathrm{m}.$ It is $10 \mathrm{m}$ deep. If the inner curved surface area of the well is $k {\mathrm{m}}^2$, then find the value of $k$. (Take $\mathrm{\pi }=\frac{22}{7}$)

The inner diameter of a circular well is $3.5 \mathrm{m}$. It is $10 \mathrm{m}$ deep. Find the cost of plastering this curved surface at the rate of $\mathrm{₹}\mathrm{}40$ per ${\mathrm{m}}^2$. [Use, $\pi =\frac{22}{7}$ and  write only numerical value without rupee symbol]

In a hot water heating system, there is a cylindrical pipe of length $28 \mathrm{m}$ and diameter $5 \mathrm{cm}.$ If the total surface area of radiating surface in the system is $k {\mathrm{m}}^2$, then find the value of $k$. (Assume $\mathrm{\pi }=\frac{22}{7}$)

If the lateral or curved surface area of a closed cylindrical petrol storage tank that is $4.2 \mathrm{m}$ in diameter and $4.5 \mathrm{m}$ high is $k {\mathrm{m}}^2$. $\left(\mathrm{Use} \pi =\frac{22}{7}\right)$, then find $k.$

If $k {\mathrm{m}}^2$ steel  was actually used and $\frac{1}{12}$ of the steel actually used was wasted in making the tank that is $4.2 \mathrm{m}$ in diameter and $4.5 \mathrm{m}$ high, find $k$. $\left(\mathrm{Use} \pi =\frac{22}{7}\right)$

The students of a Vidyalaya were asked to participate in a competition for making and decorating penholders in the shape of a cylinder with a base, using cardboard. Each penholder was to be of radius $3$ cm and height $10.5 \mathrm{c}\mathrm{m}$. The Vidyalaya was to supply the competitors with cardboard. If there were $35$ competitors, how much cardboard $\left(\mathrm{in} {\mathrm{cm}}^2\right)$ was required to be bought for the competition? $\left(\mathrm{Use} \pi =\frac{22}{7}\right)$