Area and Volume

This presentation is about drawing to the scale, measuring area and volume of an object and understanding its importance.

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. 1 metre 1 metre one square metre 2 metres 3 metres Six square meters

3. Area of a Triangle 4 metres 4 metres 5 metres 4 metres Area of a triangle = 0.5 x base x height Height Height Base Base Area = 8 square metres Area = 10 square 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. Circumference = 3.14 x diameter Diameter Radius Circumference = 3.14 Area = 3.14 x radius 2 (radius 2 = radius x radius ) Working with circles…

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

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 1 metre 1 metre Volume of the square = one cubic metre 1 metre

10. 2 metres 3 metres Volume = 12 cubic metres 2 metres 1 metre 0.5 metres Volume = 1 cubic metre 2 metres More examples …

11. Volume of a Cylinder radius height 3 metres Volume = 36 cubic metres Area of a circle = X radius 2 (radius 2 = radius x radius ) Volume of a cylinder = Height x Area So, Volume of the given cylinder = 3 x 12 = 36 m 3 Area of the base of the given cylinder = 3 x 2 x 2 = 12 m 2 2 metres Volume of a cylinder is simply the area of the base (area of a circle ) multiplied by the height of the cylinder.

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