Page 151 - ICSE Math 5

The shaded part in the given figures show the amount of
Remember
region enclosed, i.e., their area. Area is measured in square
units such as square mm or square cm or square m or any The units which are
used to measure area
other square unit. Square mm, square cm and square m can
depends on the units of
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also be written as mm ,cm and m respectively. length such as mm, cm, m
2
2
Let’s find the area of plane figure and an irregular figure by and km.
counting the number of squares enclosed by it through an
example.

Example 8: Find the area of the given figures by counting the number of squares where the
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area of each square measures 1 square cm (cm ).
(a) (b)

Solution: (a) Number of squares covered by the given figure = 15

Area of 1 square = 1 square cm
 Area of 15 squares = 15 × 1 square cm

= 15 square cm or 15 cm 2
So, the area covered by the given figure is 15 cm . A B C D 3
2
(b) Number of whole squares = 7 (a, b, c, d, e, f and g) E a b c F
1 1
Number of half squares = 2 (1 and 2), i.e., + = 1 G d e f 1
2 2
Number of squares that cover more than half H g I
2 J
= 10 (A, B, C, D, E, F, G, H, I and J)

Number of squares that cover less than half = 1 (so neglect it)
 Approximate area of the given figure = 7 + 1 + 10 = 18
So, the approximate area of the given figure is 18 cm .
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We can also say that an area of a plane figure refers to the number of square units it covers.

Now let’s learn to find the area of some simple geometrical figures using formula.
Area of a Rectangle

Look at the figure given alongside where a rectangular
board has been tiled using 14 square tiles, each of side 2 cm
1 cm. Thus, each square tile has an area of 1 cm . Let’s
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find the area of the rectangular board. 7 cm

Length of the rectangular board = 7 cm
Breadth of the rectangular board = 2 cm

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