# Y8MA3G_Perimeter and Area_11_01_2012

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Category: Education

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### Perimeter & Area of rectangles :

Perimeter & Area of rectangles Lesson objective: To be able: to calculate the perimeter and the area of rectangles. [Level 5] Key words: perimeter area units of measurement Starter: Draw a rectangle ABCD. Which sides are: equal , ii) parallel, iii) perpendicular ? How many degrees are there in each angle?

### Slide 2:

Perimeter: is the total distance around the shape. Perimeter = 2 lengths + 2 widths P = 2l + 2w Formula 6 cm The units used to measure perimeter are mm, cm, or m. 4 cm P = 2l + 2w = 2x6 + 2x4 = = 12 + 8 = 20 cm OR P = 6 + 4 + 6 + 4 = 20 cm length width

### Slide 3:

Area: is the amount of space inside the shape. Area = length x width A = l x w Formula 6 cm The units used to measure area are mm², cm², or m². 4 cm A = l x w = 6 x 4 = 24 cm² length width

### Slide 4:

5 m 3 m P = ? A = ? P = 5 + 3 + 5 + 3 = P = 16 m A = 5x3= A = 15 m² Example…

### Slide 5:

Work in pairs… By measuring the length of the sides of the following rectangles, find: the perimeter the area

### Slide 6:

Work in pairs… For each of the following rectangles, find: the perimeter the area Remember to use the correct units.

### Slide 7:

P = ? A = ? P = 2+8+2+8 = = 20 cm A = 2x8= A = 16 cm² Example… Draw a rectangle with sides 8cm and 2cm. Then find the perimeter and the area. 8cm 2cm

### Slide 8:

Plenary… Match the below… 12 cm 8 cm² 4cm 2cm 4 cm 1 cm² 1cm 1cm Perimeter Area