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For measuring larger areas, we use larger
units of area. Square metre (or sq. m) is one
such unit. One square metre is the area of a Keep in Mind
square in which each side is 1 metre in length.
1 m = 100 cm
The area of a rectilinear figure is calculated by 1 m × 1 m = 100 cm × 100 cm
counting the number of squares inside the figure. 1 sq. m = 10,000 sq. cm

However, sometimes the figure is non-rectilinear
and passes through a square covering only a small portion (less than half) or
sometimes half or more. In such cases, calculating the area of the figure requires a
little caution. When a shape passes through a square, covering less than half of its
area, that portion is not counted. If the shape covers more than half of the square,

1
1 square unit is added to the total area. For a square that is exactly half covered,
2

square unit is added. A fully covered square inside the figure automatically contributes
1 square unit to the total area.

example 1. Find the area of the square Solution.
considering the area of 1 2 3 4 5
1 square box = 1 sq. cm.
6 7 8 9 10
11 12 13 14 15

16 17 18 19 20
21 22 23 24 25

Mark numbers inside the square boxes.
Here, total number of complete squares
= 25.

So, the area of the square = 25 sq. cm.
example 2. Find the area of the given figure.

Solution. The circle is passing through square boxes that cover less than half or more
than half of the boxes. Hence, we have to calculate the number of boxes separately.

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Perimeter and Area