Page 145 - Maths Class 06

If in rectangle PQRS RS, = 20 cm then PQ is also of the same length i e. ., 20 cm. S R
Also, if QR = 8 cm, then SP = 8 cm. 8 cm
Perimeter of the figure = PQ + QR + RS + SP

= 20 cm + 8 cm + 20 cm + 8 cm P 20 cm Q
= 56 cm

Perimeter of a Square
L l O
Let LOVE be a square such that the length of each of its side = l
\ Perimeter of square = LO + OV + VE + EL l l
= + + + =l l l l l 4

\ Perimeter of square = ´4 l, where l = length of one of its sides. E l V
EXAMPLE 1. Find the perimeter of rectangular field whose length and breadth are 100 m and 80 m,
respectively.
SOLUTION : Length of the field (l) = 100 m

Breadth of the field ( )b = 80 m
Perimeter of the field = 2 (l + ) b 80 m Field

= 2 (100 + 80)
= 2 × 180 m 100 m
= 360 m

Hence, the perimeter of the field is 360 m.
EXAMPLE 2. A square sheet of paper has a perimeter of 48 cm. What is the length of each side?

SOLUTION : Perimeter of square sheet = 48 cm
4 × side = 48 cm
48
side = cm = 12 cm
4
Hence, a side of the square sheet is 12 cm.

EXAMPLE 3. A rectangular field is 34 m long and 26 m wide. What would be the total cost of fencing the
field if the fencing rate is ` 50 per m?
SOLUTION : Length of the field ( )l = 34 m
Breadth of the field ( )b = 26 m

Perimeter of the field = 2 (l + ) b
NOTE
= 2 (34 + 26) m
Perimeter of a figure is measured in m or
= 2 × 60 m
cm not in square cm or square m.
= 120 m
Cost of fencing 1 m field = ` 50

Cost of fencing 120 m field = ` (120 × 50)
= ` 6000

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