Volume of a Cylinder = area of circular base × height 
= $πr^2h$
where $r$ is the base radius and $h$ is the height of the cylinder
EXERCISE 13.6
Assume π = $22/7$ unless stated otherwise
1. The circumference of the base of a cylindrical vessel is 132 cm and its height 
is 25 cm. How many litres of water can it hold? (1000 $cm^3$ = 1 $l$)

2. The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter
is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 $cm^3$ of 
wood has a mass of 0.6 g.

3. A soft drink is available in two packs – (i) a tin can with a rectangular base
of length 5 cm and width 4 cm, having a height of 15 cm and (ii) a plastic cylinder
with circular base of diameter 7 cm and height 10 cm. Which container has greater
capacity and by how much?

4. If the lateral surface of a cylinder is 94.2 $cm^2$ and its height is 5 cm, then find
(i) radius of its base (ii) its volume. (Use π = 3.14)

5. It costs ₹ 2200 to paint the inner curved surface of a cylindrical vessel 10 m deep.
If the cost of painting is at the rate of ₹ 20 per $m^2$, find
(i) inner curved surface area of the vessel,
(ii) radius of the base,
(iii) capacity of the vessel.

6. The capacity of a closed cylindrical vessel of height 1 m is 15.4 litres. How many
square metres of metal sheet would be needed to make it?

7. A lead pencil consists of a cylinder of wood with a solid cylinder of graphite
filled in the interior. The diameter of the pencil is 7 mm and the diameter of the 
graphite is 1 mm. If the length of the pencil is 14 cm, find the volume of the wood
and that of the graphite.

8. A patient in a hospital is given soup daily in a cylindrical bowl of diameter 7 cm.
If the bowl is filled with soup to a height of 4 cm, how much soup the hospital has to 
prepare daily to serve 250 patients?