Page 201 - Start Up Mathematics_6

MATHS LAB ACTIVITY

Finding Area of Irregular Figures

Can you guess the area of the given figure by just looking at
it? We follow these steps for a fair estimate of area. L

(i) Place the figure on a squared paper.

(ii) Draw an outline of the figure on the squared paper. F
(iii) Count the number of complete squares covered by the

irregular figure (i.e., fully-filled squares like F). Let’s
say these are f in number. M H

The area of one fully-filled square is taken as 1 sq. unit.
In case of centimetre square sheet, area of 1 full square
is 1 sq. cm.

(iv) If more than half of the square is included in the region, (i.e., more than half-filled squares
like M), count it as 1 square. Let’s say these are m in number.
1
(v) If exactly half of the square is included in the region (i.e., like H), count it as 2 square.
Let’s say these are h in number.

(vi) Ignore the squares which cover or include less than half of the region (i.e., like L).
h
The approximate area of the given irregular figure is = f + m + sq. units
2
Is your guess close to the fair estimate of 30.5 cm obtained by the above method?
2
You can take cutouts of any plane figures such as dry leaves of different trees to find their approximate
areas.

Example 12: Find the area of the following figures by counting squares:

(a) (b) (c)

(d) (e) (f)

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