Calculating area

Area is the amount of space taken up by a 2D shape.
When you want to measure the space on a wall, floor or a piece of paper, you are measuring area.
Area can be measured in square centimetres (cm²) and square metres (m²).
If you know the width and height of a rectangle, you can split it into squares and count them, to figure out its area.
You can also work out the area by multiplying the width and height together.

Activity: How to work out an area
Complete this interactive activity to understand how to work out an area. Then put your knowledge to the test.
Counting or multiplying to find the area
To work out the area of a rectangle, you must know the width and height.

This rectangle has a width of 8cm and a height of 2cm.
You can then split the rectangle into squares and count them to discover its area.

You can see that this rectangle contains 2 rows of 8 squares. That is 16 squares in total.
You can also find the area of a rectangle by multiplying the width and height together.

The area of this rectangle is:
8cm × 2cm = 16cm²
Example 1

What is the area of this shape?
✓21m²
To find the area of the shape you can split the rectangle into squares and count them, or multiply the width by the height.
7m x 3m = 21m²

Example 2

What is the area of this shape?
✓24cm²
To find the area of this complex shape, you can cut it into two rectangles and then work out the area of each.

The larger rectangle measures 8cm by 2cm.
8cm × 2cm = 16cm²
The smaller rectangle measures 4cm by 2cm.
4cm × 2cm = 8cm²

The total area is then calculated by adding both together.
6cm² + 8cm² = 24cm²
Example 3

The area of this rectangle is 24m². What is the width?
✓4m
Divide the area by the length of one of the known sides to find the missing side measurement.
24m² ÷ 6m = 4m

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More on 2d shapes
Find out more by working through a topic
- count8 of 10

- count9 of 10

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- count1 of 10
