This presentation discusses calculating the area and volume of objects by understanding basic units of measurement, how to measure the area of different shapes like triangles and circles, and how to calculate the volume of cubes, cylinders and other objects by multiplying measurements of length, width, and height or radius. Examples are provided for calculating materials needed for projects like covering roofs based on area and how much paint or water a container can hold based on volume.

1. Area and Volume
This presentation is about drawing to the
scale, measuring area and volume of the
object and to understand why it is
important.
In order to understand this lesson, students need
to be aware of the units like metres and
centimetres and they should also know how to
convert them. They must also understand how to
multiply and divide, as well as having access to a
calculator, pencil and compass.

2. To construct or to make anything you will need some sort of material.
You will also need to know the amount of material required for it. How
to calculate it? Let’s see.
Materials such as plastic and plywood etc.are always sold per square
metre.
one square
1 metre
metre 2 metres
Six square meters
1 metre
3 metres

3. Area of a Triangle
Area of a triangle = 0.5 x base x height
4 metres
4 metres
Area = 10 square metres
Area = 8
Height
Height
square metres
Base 4 metres Base 5 metres

4. Lets take some examples so that you will
be able to calculate the exact amount of
material required for different things.
•Assume that you need to cover the roof
of a chicken hut with plastic
sheet to make it
waterproof. So, how much
plastic sheet you should buy?
•Assume that you need to cover roof of
your bamboo hut with new
plywood. How much plywood
you have to buy to cover it?
•Assume that you have build a weather
station. You have to cover its
roof with metal sheet. How
much metal sheet you will need
for it?
(** You can decide measurements of the above
imaginary structures as per your wish.)

5. Activity
You are asked to paint all the four sides of a bamboo hut
and a weather station.
•How many pots of paint you will need?
•How much will it cost to paint both the things?
** 1 pot of paint
paints 2 square
metres
** Price of the paint
is Rs. 50 per pot

6. Here is the hint...
?
Find out the area of your design to cover.

7. Working with circles…
= 3.14
Area = 3.14 x radius2
Diameter (radius2 = radius x radius)
Circumference = 3.14 x diameter

8. Activity
Find out any cylindrical object and then calculate the
area and circumference of the base of that object.

9. Volume
Volumes are measured in cubic metres.
Volume = base x length x height.
1 metre
1 metre
Area of the square = one square metre
Volume of the square = one cubic metre

10. More examples …
Volume = 12
cubic metres
Volume = 1
cubic metre
0.5 metres

11. Volume of a Cylinder
Volume of a cylinder is simply the area of the base (area
of a circle) multiplied by the height of the cylinder.
Area of a circle = X radius2
(radius2 = radius x radius)
Area of the base of the given cylinder
=3x2x2
= 12 m2
Volume of a cylinder
= Height x Area
3 metres
height
So, Volume = 36
cubic metres
Volume of the given cylinder
= 3 x 12 = 36 m3

12. Volume is useful, particularly when finding out how much
water or liquid a tank can hold. This would also be useful
when seeing how much food could be packed into crates,
or how much liquid a bottle can hold.
Activity
Check out a nearby household water tank.
Now, calculate how many litres of water the tank can hold?
Hint: 1 cubic metre = 1000 litres