Dr Pooranmal and Ashfaq A Khan Solutions for Chapter: Mensuration, Exercise 3: EXERCISE 20.3

Find the surface area (in ${\mathrm{cm}}^2$) of a cube, whose edge is $6 \mathrm{cm}$.

A cuboidal box is $4 \mathrm{cm}$ by $3 \mathrm{cm}$ by $5 \mathrm{cm}$. Find its surface area.

Find the surface area (in ${\mathrm{cm}}^2$) of a cube, whose volume is $216 {\mathrm{cm}}^3$.

The dimensions of a cuboid are in the ratio $5:3:1$ and is total surface area is $414 {\mathrm{m}}^2$. Find the dimensions.

A tank $12 \mathrm{m}$ by $8 \mathrm{m}$ by $5 \mathrm{m}$ is to be made. It is open at the top. Find the cost of iron sheet, at the rate of

$₹12$ per $\mathrm{meter}$. If the sheet is$4 \mathrm{m}$ wide.

A swimming pool is $20 \mathrm{m}$ long $15 \mathrm{m}$ wide and $4 \mathrm{m}$ deep. Find the cost of repairing its floor and four wall $@ ₹ 5.25$ per square metre.

The cuboid have total surface area of $50 {\mathrm{m}}^2$ and lateral surface area is $30 {\mathrm{m}}^2$. Find the area of its base.

A barn with a flat roof rectangular in the shape of breadth $10 \mathrm{m}$, length $15 \mathrm{m}$ and height $5 \mathrm{m}$. It is to be painted inside on the walls and on the ceiling but not on the floor. If the total area to be painted is $k {\mathrm{m}}^2$, find the value of $k$