Area and VolumeThis presentation is about drawing to thescale, measuring area and volume of theobject and to understand why it isimportant.In order to understand this lesson, students needto be aware of the units like metres andcentimetres and they should also know how toconvert them. They must also understand how tomultiply and divide, as well as having access to acalculator, pencil and compass.
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. Howto calculate it? Let’s see.Materials such as plastic and plywood etc.are always sold per squaremetre. one square1 metre metre 2 metres Six square meters 1 metre 3 metres
Area of a Triangle Area of a triangle = 0.5 x base x height 4 metres4 metres Area = 10 square metres Area = 8Height Height square metres Base 4 metres Base 5 metres
Lets take some examples so that you willbe able to calculate the exact amount ofmaterial 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 aboveimaginary structures as per your wish.)
ActivityYou are asked to paint all the four sides of a bamboo hutand 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
Here is the hint... ? Find out the area of your design to cover.
Working with circles… = 3.14 Area = 3.14 x radius2 Diameter (radius2 = radius x radius) Circumference = 3.14 x diameter
ActivityFind out any cylindrical object and then calculate thearea and circumference of the base of that object.
Volume Volumes are measured in cubic metres. Volume = base x length x height. 1 metre 1 metreArea of the square = one square metre Volume of the square = one cubic metre
More examples … Volume = 12 cubic metres Volume = 1 cubic metre 0.5 metres
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 m2Volume of a cylinder= Height x Area 3 metres heightSo, Volume = 36 cubic metresVolume of the given cylinder= 3 x 12 = 36 m3
Volume is useful, particularly when finding out how muchwater or liquid a tank can hold. This would also be usefulwhen seeing how much food could be packed into crates,or how much liquid a bottle can hold.ActivityCheck out a nearby household water tank.Now, calculate how many litres of water the tank can hold? Hint: 1 cubic metre = 1000 litres