Answer:

PS = l and PQ = b

Perimeter of a Rectangle

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Perimeter of the rectangle = PQ + QR + RS + SP

= b +l + b + l

= 2b +2l

Again,

ABCD is a rectangle. We KNOW that the opposite sides of a rectangle are equal.

Perimeter of a Rectangle

AB = CD = 5 cm and BC = AD = 3 cm

So, the perimeter of the rectangle ABCD = AB + BC + CD + AD = 5 cm + 3 cm + 5 cm + 3 cm = 16 cm

It can be written as 5 cm + 5 cm + 3 cm + 3 cm

= (2 × 5) cm + (2 × 3) cm

= 2 (5 + 3) cm

= 2 × 8 cm

= 16 cm

We add length and breadth twice to FIND the perimeter of a rectangle.

Perimeter of a rectangle = 2 (length + breadth)

Let us consider some of the examples on perimeter of a rectangle:

1. The length of a rectangle is 4 cm and its breadth is 2 cm. Find its perimeter.

Solution:

Length = 4 cm

Breadth = 2 cm

Examples on Perimeter of a Rectangle

Therefore, perimeter of the rectangle

= 2 (length + breadth)

= 2 (4 + 2) cm

= 2 × 6 cm

= 12 cm

2. A rectangular swimming pool is 9 m long and 4 m broad. Find the area of the swimming pool.

Solution:

Length of the rectangular swimming pool = 9 m

Breadth of the rectangular swimming pool = 4 m

Therefore, perimeter of the rectangle swimming pool

= 2 (length + breadth)

= 2 (9 + 4) m

= 2 (13) m

= 2 × 13 m

= 26 m

3. The length of a rectangle is 4.5 m and the breadth is 1.5 m. Find the perimeter.

Solution:

Length = 4.5 m

Breadth = 1.5 m

Perimeter of a Rectangle Problems

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Perimeter = 2(length + breadth)

= 2 × (4.5 m + 1.5 m)

= 2 × 6 m

= 12 m

Therefore, the perimeter is 12 m.

4. A rectangle DISPLAY board is measuring 8 m by 6 m. Robert wants to add a ribbon border around the display board. What is the length of ribbon that he will need? If the cost of the ribbon is $ 15 per metre then how much money does Robert needs to buy the ribbon?

Solution:

Length of the display board = 8 m

Breadth of the display board = 6 m

Perimeter of the display board = 2(Length + Breadth)

= 2(8 + 6) m

= 2 × 14 m

= 28 m.

Cost of ribbon is $15 per metre.

Therefore, total cost for 28 m long ribbon = $15 × 28

= $420.