Perimeter

Perimeter The perimeter of a closed figure is the total measure of the boundry. Rahman is a farmer. He has to fence his field What length of the barbed wire I should buy to fence my field? The answer is, I should buy 8 m + 12 m +10 m + 4 m = 34 m barbedwire.

First we need to find he length of each side by counting the squares. 8 cm The distance around the outside of a shape is called the perimeter. 6 cm 6 cm 8 cm The perimeter of the shape is 8 + 6 + 8 + 6 = 28cm.

18cm 18cm What is the perimeter of each of these shapes? Your teacher will give you copy of the worksheet. 22cm 18cm 26cm

Calculate the perimeter

Perimeter of a Rectangle 2 + 4 + 2 + 4 2 4 To calculate the perimeter of an object or space, you will need to add the length and width, then multiply by 2. ( 2 + 4 ) x 2 = ______

Perimeter of Rectangle Formula We know that, the perimeter of rectangles with different lengths and breadths is length + breadth + length + breadth Perimeter = 2 x length + 2 x breadth = 2 (length + breadth) = 2 (l + b) units where ‘l’ denotes the length and ‘b’ denotes the breadth. So, Perimeter of a rectangle = 2 (l + b) units

Example 1: Find the perimeter of a rectangle, whose length is 6 cm and breadth is 2 cm. Solution: Method 1: Perimeter = Length + Breadth +Length +Breadth = 6 + 2 + 6 + 2 = 16cm Method 2: Perimeter = 2 x (l+b) units = 2 x (6+2) = 2 x 8 = 16 cm 2 6

Example 2: Find the perimeter of a rectangle, whose length is 8 cm and breadth is 4 cm. Solution: Method 1: Perimeter = Length + Breadth +Length +Breadth = 8 + 4 + 8 + 4 = 24cm Method 2: Perimeter = 2 x (l+b) units = 2 x (8+4) = 2 x 12 = 24 cm

Try to find the perimeter of these rectangles. 1 8 2 3 3 5 4 3

To find the perimeter of a square, multiply the side by 4. 3 + 3 + 3 + 3 To find the perimeter of a square, multiply the side by 4. 3 x 4 = ___ 3

Perimeter of Square using Formula Every square is a rectangle whose length and breadth are equal. Perimeter = 2 x side + 2 x side = 4 x side = 4s, where‘s’ is the side. So, Perimeter of a square = 4 x side units

Find the perimeter of a square whose side is 20 cm. Solution: Example 1: Find the perimeter of a square whose side is 20 cm. Solution: Method 1: Perimeter = side + side + side + side = 20 + 20 + 20 +20 = 80 cm Method 2: Perimeter = 4 x side = 4 x 20 = 80 cm 20

Example 1: Find the perimeter of a square whose side is 24 cm Example 1: Find the perimeter of a square whose side is 24 cm. Solution: Method 1: Perimeter = side + side + side + side = 24 + 24 + 24 +24 = 96 cm Method 2: Perimeter = 4 x side = 4 x 24 = 96 cm

Find the perimeter of these squares. 25 5 12 16 8

Perimeter of a Triangle 5 3 4 To calculate the perimeter of a triangle you will need to add the sides. 3 + 4 + 5 = 12 (Just add all three sides)

Find the perimeter of the following triangles 5 4 6 7 4 6 8 To calculate the perimeter of a triangle, you will need to add the sides. 5 + 6 + 4 = 15 (Just add all three sides) To calculate the perimeter of a triangle, you will need to add the sides outside. 6 + 7 + 8 = 21 (Should not take 4 as 4 is inside the triangles)

Find the perimeter of these triangles. 5 3 3 4 6 4 7 3 3 8 3

Perimeter = Adding all the sides of the above shape Find the Perimeter 2 cm 2 cm 3 cm 3 cm 4 cm 6 cm 6 cm 8 cm Perimeter = Adding all the sides of the above shape = 2 + 3 + 4 + 3 + 2 + 6 + 8 + 6 = 34 cm

Find the perimeter 5cm 2cm 6cm 11cm 2cm 4cm 5cm 4cm 9cm 5cm 4cm 2cm