area and perimeter

Slide 1 : AREA AND PERIMETER

The Perimeter : The Perimeter

Slide 3 : Take a walk around the edge! 6cm 10 cm The perimeter is… 32cm ! 6 16 22 32

Slide 4 : Take a walk around the edge! 8cm 10 cm The perimeter is… 26 cm ! 8cm 8 16 26

Slide 5 : Take a walk around the edge! The perimeter is… 32 cm ! This is a regular octagon with sides 4 cm 4 8 12 16 20 24 28 32

Slide 6 : Take a walk around the edge! The perimeter is… 60 cm ! This shape has sides of 5 cm each 15 30 45 60

Slide 7 : 8 cm 6 cm 8 cm 6 cm The perimeter of the shape is 8 + 6 + 8 + 6 = 28cm. First we need to find he length of each side by counting the squares.

Slide 8 : What is the perimeter of each of these shapes? 18cm 18cm 18cm 22cm 26cm

Slide 9 : Now find the perimeter of these shapes. They are not drawn to scale. Perimeter = 18cm Perimeter = 22cm Perimeter = 28cm

Slide 10 : Area is the measure of how much space a shape takes up. We measure it in squares such as square centimetres or metres etc. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 This rectangle takes up 28 squares. It has an area of 28 square centimetres 28 cm2

Slide 11 : The area of the shape is 18cm2. To find out how much shape is inside we can count the squares.

Slide 12 : What is the area of each of these shapes? 12cm2 26cm2 26cm2

Slide 13 :

Slide 14 : The area of the shape is 60cm2.

Slide 15 : What is the area of each of these shapes? Your teacher will give you copy of the worksheet. 24cm2 25cm2 22cm2 35cm2

Slide 16 : The area of the shape is 48cm2. The rectangle is made of 6 rows of 8 squares. To work out the number of squares we times 6 by 8.

Slide 17 : What is the area of each of these shapes? 20cm2 18cm2 14cm2 30cm2 22cm2

Slide 18 : We can work out the area of a rectangle without the grid. length width Area = length x width

Slide 19 : It could take a long time to cover shapes in squares. Luckily there is an quicker way. 7 cm 4 cm × = 28 cm2

Slide 20 : Now work out the area of these rectangles. They are not drawn to scale. 36cm2 35cm2 20cm2 25cm2 4cm 9cm 7cm 5cm 5cm 4cm 2cm 12.5cm

Slide 21 : Can you find the areas of these rectangles? 15 cm2 14 cm2 49 m2

Slide 22 : Can you think of a way to find the area of this shape? 12 cm 6 cm 5 cm 7 cm 3 cm

Slide 23 : Split the shape into rectangles? 12 cm 6 cm 5 cm 7 cm 3 cm

Slide 24 : Find the area of each rectangle? 6 cm 5 cm 7 cm 3 cm 5 × 6 = 30 cm2 7 × 3 = 21 cm2

Slide 25 : Add the areas together to find the area of the complete shape? 30 + 21 = 51 cm2 30 cm2 21 cm2

Slide 26 : A shape that is made from other shapes is known as a composite shape. To find the area of this shape we have to split it up into two rectangles. 10cm 8cm 8cm 2cm 4cm 4cm Area = 4 x 10 40cm2 Area = 4 x 8 32cm2 Total area = 40 + 32 = 72 cm2

Slide 27 : Find the area and perimeter of each of these shapes? Your teacher will give you copy of the worksheet. 9cm 5cm 5cm 2cm 4cm 5cm 4cm 2cm 11cm 7cm 4cm 3cm 3cm 3cm 7cm 4cm

Slide 28 : 9cm 5cm 5cm 2cm 4cm 5cm 4cm 2cm Area = 5 x 9 45cm2 Area = 4 x 5 20cm2 Total area = 45 + 20 = 65 cm2 Perimeter = 36 cm

Slide 29 : Area = 2 x 5 10cm2 Area = 6 x 6 36cm2 Total area = 10 + 36 = 46 cm2 Perimeter = 34 cm

Slide 30 : 11cm 7cm 4cm 3cm 3cm 3cm 7cm Total area = 28 + 16 + 21 = 65 cm2 Perimeter = 42 cm Area = 4 x 7 Area = 4 x 4 4cm Area = 3 x 7 21cm2 28cm2 16cm2 There is another way of doing this question.

Slide 31 : 11cm 7cm 4cm 3cm 3cm 3cm 7cm Total area = 77 – 12 = 65 cm2 Perimeter = 42 cm Area = 7 x 11 Area = 3 x 4 4cm 77cm2 12cm2

Slide 32 : Here is a challenge can you work out the area of this shape with a hole in it? 10 cm 5 cm 5 cm 2 cm Clue: Take the area of the hole from the area of the whole! 50 cm2 – 10 cm2 = 40 cm2

Slide 33 : Well Done THANK YOU

Slide 34 : Review What is the area of the moon? _____________________cm2 What is the area of the rectangle? _____________________cm2 What is the perimeter of the rectangle? _____________________cm Name:____________________

Slide 35 : 4cm 4cm 4cm 6cm 8cm 2cm What is the area of the compound shape? _____________________cm2 What is the perimeter of the compound shape? _____________________cm What is the area of the house? _____________________cm2