CLASS-4
CONCEPT OF AREA
CONCEPT OF AREA -
Take some balls. Cover your balcony with these.
How many balls do you need to cover the balcony of your house?
Now ask you friend to do the same. Who needs more balls? Whose hand has a larger surface?
Washing a bedsheet takes longer than washing a towel because a bedsheet has a greater surface area than a towel.
So, by area we mean the flat surface which you cover or paint.
The surface enclosed within the boundary of a figure is called its area.
It helps to imagine how much paint would cover the shape.
STANDARD UNIT OF AREA -
To measure small areas we use a square whose each side is 1 centimeter.
The area of this square is 1 square centimeter written as 1 sq cm.
To measure big areas, such as area of cricket ground, we use a square whose each side is 1 meter.
The area of this square is 1 square meter written as 1 sq m.
Bigger areas are measured in square kilometer.
Area by Counting Squares -
We can also put the shape on a grid and count the number of squares:
The rectangle has an area of 15.
Example: When each square is 1 meter on a side, then the area is 15 m² (15 square meters)
Be careful to say "square meters".
There are also "square mm", "square dm" etc,.