1. AREA

2. Area is the space a shape takes up (Perimeter is the distance around it)
Look at this square – its made of 4 smaller cm squares – its area is 4cm². This rectangle is made of 6 smaller cm Squares – its area is 6cm². So for EVERY rectangle the area is Base x Height
2cm
2cm
3cm

3. Area of a triangle
This rectangle is divided into 2 congruent triangles. The area of the rectangle is base x height. This is the area of both triangles together. So the area of one triangle is ½ x base x height
height
base

4. Area of a parallelogram
height
base
Each triangle has area ½ x base x height.
So the parallelogram has area two times that.
Area of a parallelogram is base x height.

5. Circles sector segment You need to learn these tangent radius chord
circumference
You need to learn these

6. Circles or C = 2 x π x r The circumference of a circle is
π x diameter
Use this formula to work out the circumferences of circles with diameters 12cm, 25mm and 1.23m.
The diameter is 2 x radius.
This means the circumference can also be written as 2 x r x π
or C = 2 x π x r
Use this formula to work out the circumferences of circles with radii 8cm, 12mm and 2.9m.

7. Area of a circle We chop the circle into sectors and fit them
together...
This does not quite make a rectangle...
But each side is half the circumference,
And the base is the radius.
We chop the circle into many more sectors and
fit them together...
This now makes an approximate rectangle...
Again each side is half the circumference,
And the base is the radius.

8. Area of a Circle Area of a circle = πr²
½ circumference
radius
Shaded area = ½ Circumference x r
(And circumference = 2 x π x r)
So shaded area = π x r x r and is the same as
Area of a circle = πr²

9. Area of a Circle Area of a circle = πr² Find the areas of the circles
With radii 14cm, 80mm and 1.25m
With diameters 16cm, 48cm and 2.8m
Don’t forget to use the correct units.

10. Areas of complex shapes
Chop the shape into smaller ones you can deal with.
We now have 2 rectangles
A x 30 = 150
B x 60 = 300
Total area is 450 B A
Try these

11. This is the outside area of a 3 dimensional shape.
Surface Area
This is the outside area of a 3 dimensional shape.
This cylinder is made up from 2 circles and a rectangle
curved around, joining them.
The area of the rectangle = circumference of the circle
x height
π x 2 x 10 x 15
300π
942.5cm²
The area of the circles = 2 x π x 10 x 10
200π
628.3cm²
Total surface area =
1571cm²
15cm
10 cm

12. Surface Area A triangular prism Work out the areas of each shape
Add them together!