Square and Rectangle

Chapter 9 Class 7 Perimeter and Area
Concept wise

Let’s take a square

We know that

In a square, all sides are equal

AB = BC = CD = AD

Let AB = a

So,

AB = BC = CD = AD = a

Now,

Perimeter of square = Sum of all sides

= AB + BC + CD + AD

= a + a + a + a

= 4a

= 4 × Side of square

So,

Perimeter of square = 4a

= 4 × Side of square

Let’s solve some examples

#### Find perimeter of a square whose side is 15 cm

Given,

Side of square = a = 15 cm

So,

Perimeter of square = 4 × side of square

= 4a

= 4 × 15

= 60 cm

Thus, Perimeter of square is 60 cm

#### Find perimeter of a square whose side is 0.5 m

Given,

Side of square = a = 0.5 m

= 0.5 × 100 cm  (1m = 100 cm)

= 50 cm

So, Perimeter of square = 4 × Side of square

= 4a

= 4 × 50

= 200 cm

= 200/100 m         (1 cm =  1/100 m )

= 2 m

#### Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.