1. Level 4/5 Booster
Lesson 9B
Area and Perimeter

2. 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

3. 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 x 12 cm rectangle with a perimeter of 26cm.
Even greater perimeters are achieved if decimal lengths are acceptable!!!
( Example x 120cm perimeter is 240.2cm.)

4. 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

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

6. 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

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

8. 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)
= 900cm²

9. 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

10. Thank you for your attention