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1. Complete the following table.

Length of a Rectangle Breadth of a Perimeter of a Area of a Rectangle
Rectangle Rectangle
(a) 5 cm 3 cm

(b) 8 cm 36 cm
(c) 12 m 216 sq. m
(d) 14.5 cm 72 cm

2. Find the perimeter and the area of the following squares.

(a) square of side 8 cm (b) square of side of 3.4 m (c) square of side 78 mm
3. The length of three sides of a triangle is 14 cm, 33 cm, 25 cm. Find its perimeter.

4. The length and breadth of a rectangular sheet of a paper is 36 cm and 16 cm respectively.
Find its perimeter and area.
5. Find the area of a square whose perimeter is 68 cm.

6. The length and breadth of a rectangular field are 102 m and 68 m, respectively. What is the
cost of 3 rounds of fencing the wire at the rate of `18 per metre? Also, find the cost of laying
the grass in the field at the rate of `10.5 per sq. m.

Introduction

Before to know about the area of a parallelogram, let us revise Knowledge Desk
the perimeters and areas of basic polygons like rectangle and

square. The word ‘perimeter’ comes
from the Greek word peri
Perimeter (around) and meter (measure).

The total length of the boundary of a closed plane figure is called its perimeter. E D
The unit of perimeter is same as the unit of the boundary of the figure, i.e., cm, C

m, etc.
Let ABCDE be a closed figure, then perimeter of this adjacent closed figure
A B
ABCDE = Sum of the lengths of all its sides
= AB + BC + CD + DE + EA
A l B
Let us recall the perimeter of some basic polygons.
• Perimeter of a rectangle b b
= 2 × sum of the lengths of adjacent sides D l C

= 2 × (length + breadth) units
A a B
Perimeter of a rectangle = 2 × (l + b) units

a a
• Perimeter of a square = 4 × length of its side
Perimeter of a square = 4a units D a C

281 Perimeter and Area