Level 4/5 Booster Lesson 9B Area and Perimeter

dimensions square units Objectives: Deduce and use formula for the perimeter and area of a rectangle. Calculate the perimeter and area of shapes made from rectangles. Vocabulary: dimensions square units

The area of this rectangle is 12 cm². What are the possible dimensions – length and width of this rectangle? Which of the rectangles you have found has the largest perimeter? Possible answers 1 x 12 cm 2 x 6 cm 3 x 4 cm (any other answers would involve lengths with decimals). Largest perimeter 1 x 12 cm rectangle with a perimeter of 26cm. Even greater perimeters are achieved if decimal lengths are acceptable!!! ( Example 0.1 x 120cm perimeter is 240.2cm.)

This rectangle has a perimeter of 12 cm. Find as many different rectangles with a perimeter of 12cm. Which of the rectangles has the largest area? Possible answers: 4 x 2 cm, 3 x 3 cm, 1 x 5 cm Any other answers would include decimal lengths. Largest area: 3 x 3 cm = 9cm²

- + 8cm 6cm 3cm 5cm Work out the area and perimeter of the shape. 8cm B Area is: + Perimeter: 6 + 8 + 3 + 3 + 3 + 5cm 8cm 6cm Area is: - Perimeter: Why? 3cm

Find the area and perimeter of each of the shapes below: (all measurements given in cms) 9 W/S 9.1B 8 3 3 8 5 4 4 3 2 7 4 10 5 5 2 4 7

Answers: 9 8 3 A = 40 cm² P = 30 cm 3 8 5 A = 47 cm² P = 34 cm 4 4 3 2 A = 75 cm² P = 38 cm A = 32 cm² P = 32 cm 7 4 10 5 5 2 4 7

W/S 9.2B 15m 10m 3m Calculate the area shaded green. Working: (15 x 10) – (3 x 3) = 150 – 9 = 141m² 60cm 40cm 10cm Calculate the area of the blue cross. Working: (10 x 60) + (10 x 40) – (10 x 10) 600 + 400 - 100 = 900cm²

dimensions square units Objectives: Deduce and use formula for the perimeter and area of a rectangle. Calculate the perimeter and area of shapes made from rectangles. Vocabulary: dimensions square units

Thank you for your attention