Page 90 - Mathematics_Std_4

The perimeter of a square
The perimeter of a square is the sum of the lengths of all its sides.

All sides of a square have equal length. Therefore, its perimeter
can be found by multiplying the length of one side by 4. Thus,
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Perimeter of a saquare = + length + length + length length

= ×4 length

Therefore, the perimeter of a square = ×4 l.

Example 1

Find the perimeter of the following square.

20 cm

Solution

Perimeter of a =square + length + length length length
+
+
= + 20 cm 20 cm 20 cm 20 cm
+
= 80 cm

Alternative solution

The square has four sides of equal length. It follows that,

Perimeter of a square = 4 length
×
= 20 cm 4
×
= 80 cm
Therefore, the perimeter of the square is 80 cm.

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MATHEMATICS STD 4 PB 2024.indd 83 06/11/2024 17:17:18
MATHEMATICS STD 4 PB 2024.indd 83