1. Area and Perimeter

2. Perimeter Perimeter is the distance around the outside of the object
To find a perimeter we _____ up the ________
e.g.
Perimeter = ___ + ___ + ___ + ___ + ___ = ___

3. Perimeter Perimeter is the distance around the outside of the object
To find a perimeter we add up the sides
e.g.
Perimeter = ___ + ___ + ___ + ___ + ___ = ___

4. Perimeter Perimeter is the distance around the outside of the object
To find a perimeter we add up the sides
e.g.
Perimeter = = 44

5. P= P= P=

6. P= 50 P= 25cm P= 34m

7. Area
Area is the surface an object has. How much flat space it takes up.
Each type of shape has its own rules.
The unit for area is the unit for the side with a squared sign.
cm  cm2
m  m2
km  km2

8. Rectangles and Squares
Rectangles and squares follow the basic rule about area.
AREA = WIDTH x HEIGHT 8
A = ___ x ___
= ___

9. Rectangles and Squares
Rectangles and squares follow the basic rule about area.
AREA = WIDTH x HEIGHT 8
A = x 8
= 32

10. A = _________________

11. A = 3 x 17 = 51m2
A = 10 x 52 = 520cm2
A = 50 x 70 = 3500km2

12. Cut the shape into two rectangles with a line.
Now you have 2 rectangles. You can calculate the area of each rectangle.
Top rectangle
18 x 10 = 180
Bottom rectangle
9 x 12 = 108
Total Area
= 288
Unit is cm2
A = 288cm2

13. What is the perimeter and area of this shape?

14. What is the perimeter and area of this shape?

15. Parallelograms Parallelograms are just like rectangles
AREA = WIDTH x HEIGHT
You must be careful about the number you use for height.
The height of this parallelogram is not ___ it is ___. This is because the ___ is on a lean.

16. Parallelograms are just like rectangles
AREA = WIDTH x HEIGHT
You must be careful about the number you use for height.
The height of this parallelogram is not 8 it is This is because the 8 is on a lean.

17. 7m
6cm
4cm
8cm
12m 5m

18. Triangles Triangles don't stay the same width the whole way across.
Two triangles can make a rectangle so each triangle is half as much area as the rectangle.
AREA = ½ x WIDTH x HEIGHT 7
10 A =__ x __ x __ = __

19. Triangles don't stay the same width the whole way across.
Two triangles can make a rectangle so each triangle is half as much area as the rectangle.
AREA = ½ x WIDTH x HEIGHT 7
10 A = ½ x 7 x = 35

20. Trapeziums Like a triangle the width of a trapezium changes.
We have to work out the average width. 8 14
A = (a + b) x h A = ( __ + __ ) x __
Average Width = (top side + bottom side) ÷ 2

21. Like a triangle the width of a trapezium changes.
We have to work out the average width. 8 14
A = (a + b) x h A = ( ) x 6 = 66
Average Width = (top side + bottom side) ÷ 2

22. Circles To find the area of a circle you need the radius.
The radius is the distance from the ________ of the circle to the _________.
middle
outside
radius

23. To calculate the area use the formula
π is just a number ( )
You have a calculator button for it.
Multiply it by the radius then multiply it by the radius again. You will need to round your answer.

24. e.g.
A = π r2 = x 3 x 3 = 28.27m2 3m

25. To find the perimeter of a circle (also called circumference) you need to use the formula P = 2 π r

26. e.g.
P = 2 π r = 2 x x 3 = 18.85m 3m