Q. The length, breadth and height of a room are $5m$, $4m$ and $3m$ respectively. Find the cost white washing the walls of the room and ceiling at the rate of $Rs.7.50$ per $m^2$.

Q. The paint in a certain container is sufficient to paint an area equal to $9.375m^2$. How many bricks of dimensions $22.5cm\times 10cm\times 7.5cm$ can be painted out of this container?

Q. Shanti sweets stall was placing an order for making cardboard boxes for packing their sweets. Two sizes of boxes were required. The bigger of dimensions $25cm$ $\times 20cm$ $\times 5cm$ and the smaller of dimensions $15cm$ $\times 12cm$ $\times 5cm$. For all the overlaps, $5\%$of the total surface area is required extra. If the cost of the cardboard is $4$ for $1000{cm}^2$, find the cost of cardboard required for supplying $250$ boxes of each kind.

Q. A plastic box $1.5$ m long, $1.25$ m wide and $65$ cm deep is to be made. It is opened at the top. Ignoring the thickness of the plastic sheet,
(i) determine the area of the sheet
(ii) the cost of sheet for it, if a sheet measuring $1$ m${}^2$ costs Rs.$20$.

Q. Parveen wanted to make a temporary shelter for her car, by making a box-like structure with tarpaulin that covers all the four sides and the top of the car (with the front face as a flap which can be rolled up). Assuming that the stitching margins are very small, and therefore negligible, how much tarpaulin would be required to make the shelter of height $2.5$ m, with base dimensions $4m$ $\times 3m$?

Q.

The floor of a rectangular hall has a perimeter $250m$. If the cost of painting the four walls at the rate of Rs $10$ per $m^2$ is $15000$, find the height of the hall (in meters).

Q. A cubical box has each edge $10cm$ and another cuboidal box is $12.5cm$ long, $10cm$ wide and $8cm$ high.Which box has the greater lateral surface area and by how much?

Q.

A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is $30cm$ long, $25cm$ wide and $25cm$ high.
(i) What is the area of the glass?
(ii) How much of tape is needed for all the $12$ edges?

Q. The inner diameter of a circular well is $3.5m$. It is $10m$ deep. Find
$\left(i\right)$ its inner curved surface area
$\left(ii\right)$ the cost of plastering the curved surface at the rate of $Rs.40$ per $m^2$

Q. The diameter of a roller is $84$ cm and its length is $120$ cm. It takes $500$ complete revolutions to move once over to level a playground. Find the area of the playground in m${}^2$

Q. Find
(i) The lateral or curved surface area of a closed cylindrical petrol storage tank that is $4.2m$ in diameter and $4.5m$ high.
(ii) How much steel was actually used, if $\frac{1}{12}$ of the steel actually used was wasted in making the tank?

Q. The curved surface area of a right circular cylinder of height $14cm$ is $88c{m}^2$. Find the diameter of the base of the cylinder.

Q. In a hot water heating system, there is a cylindrical pipe of length $28m$ and diameter $5cm$. Find the total radiating surface in the system.

Q. A cylindrical pillar is $50$ cm in diameter and $3.5$ m in height. Find the cost of painting the curved surface of the pillar at the rate of $12.50$ per m${}^2$.

Q.

It is required to make a closed circular cylindrical tank of height $1$ $m$ and base diameter $140$ $cm$ from a metal sheet. How many square meters of the sheet is required for the same?

Q.

In the figure, you see the frame of a lampside. It is to be covered with a decorative cloth. The frame has a base diameter of $20cm$ and height of $30cm$. A margin of $2.5cm$ is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade.

Q. 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 $3cm$ and height $10.5cm$. The Vidyalaya was to supply the competitors with cardboard. If there were $35$ competitors, how much cardboard was required to be bought for the competition?

Q. Curved surface area of a right circular cylinder is $4.4$ m${}^2$. If the radius of the base of the cylinder is $0.7$m, find its height.

Q.

A metal pipe is $77$ cm long. The inner diameter of a cross section is $4$ cm, the outer diameter being $4.4$ cm (see figure). Find its
(i) Inner curved surface area.
(ii) Outer curved surface area
(iii) Total surface area

Q. Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.