1. Sub. :- Mathematics Perimeter Std. :- 6 th Chapter no. 13

2. A perimeter is a path that surrounds an area. The word comes from the Greek peri (around) and meter (measure). The term may be used either for the path or its length - it can be thought of as the length of the outline of a shape. The perimeter of a circular area is called its circumference.area circumference In short Perimeter of a figure is the sum of the lengths of all sides of that figure

3. Perimeter of a Rectangle :- Formula 3 cm 1.5 cm P Q S R The Perimeter of a rectangle PQRS = Sum of lengths of all sides =3+1.5+3+1.5 = 3+3+1.5+1.5 =2 X length + 2 X breadth

4. The Perimeter of a rectangle = 2 X length + 2 X breadth Note :- If length & breadth of a rectangle are in Centimeters then unit of perimeter of a rectangle is cm If length & breadth of a rectangle are in Meters then unit of perimeter of a rectangle is m The Perimeter of a rectangle = 2 (l+b)

5. The length of a rectangular playground is 120 m and its breadth is 75 m. Find its perimeter. Length of a rectangular playground = 120 m breadth of a rectangular playground =75 m The Perimeter of a rectangular playground = 2 X length + 2 X breadth = 2 X 120+ 2 X 75 = 240 +150 = 390 The Perimeter of the rectangular playground is 390 m.

6. Perimeter of a Square Formula Perimeter of a Square = 4 X length = 4 X l Example: Find the perimeter 0f square whose side is 12 cm. Solution: Perimeter of a Square = 4 X lengths = 4 X l =4 X 12 =48 cm

7. Perimeter of a triangle :- Formula Perimeter of a triangle =a+b+c b a c

8. Example Find the perimeter of triangle whose sides are 10cm,12cm,14cm. solution: Given : sides of triangle :a=10 cm b=12cm c=14 cm Perimeter of a triangle =a+b+c = 10+12+14 =36 cm