Page 157 - Maths Class 05

83 = 2 × 3 + 2 × breadth

83 = 6 + 2 × breadth

83 – 6 = 2 × breadth
77 = 2 × breadth

Breadth = 77 ÷ 2 = 38.5 cm

So, the breadth of the rectangle is 38.5 cm .

Perimeter of a Square S

In the square shown, the perimeter will be the sum of all its sides.
S S
Perimeter = S + S + S + S = 4S

Perimeter of a square = 4 × side. S

Example : Find the perimeter of a square whose each side measures 9 cm .

Solution : Side of the square = 9 cm

Perimeter = 4 × side

= 4 × 9

= 36 cm

Shape Formula Example

If AB = 6 cm,

D C BC = 5 cm,
Perimeter = perimeter of rectangle
l 2 × (length + breadth) = 2 × (l + b)

or = 2 × (6 + 5)
A l B = 2 × 11

= 22 cm

If one of its sides
S
D C = 7 cm, then

perimeter of square
S S Perimeter = 4 side ABCD = 4 ×side

= 4 × 7 cm
A S B
= 28 cm

Mathematics-5 157