Introduction to Area
Discover what area means, how to count square units, and use the formula to find the area of rectangles.
What is Area?
Area is the amount of space inside a flat (2D) shape. We measure area in square units, such as square centimetres (cm²) or square metres (m²).
Area is measured in square units (cm², m²)
Counting Square Units
Count the number of squares inside the shape to find its area.
This rectangle is 5 units long and 3 units wide.
Area = 15 square units
The Area Formula for Rectangles
Instead of counting every square, we can use a formula. For a rectangle, multiply the length by the width.
Area of a Rectangle = Length × Width
Example: A Garden Bed
6 m
4 m
Area = 6 m × 4 m = 24 m²
Area of Compound Shapes
Some shapes are made from two or more rectangles joined together. To find the area, split the shape into rectangles, find each area, then add them together.
Example: L-Shaped Room
Rectangle A: 6 m × 4 m = 24 m²
Rectangle B: 3 m × 2 m = 6 m²
Total Area: 24 + 6 = 30 m²
Key Vocabulary
Area
The amount of space inside a flat shape, measured in square units.
Square Unit
A 1 × 1 square used to measure area (e.g. 1 cm² or 1 m²).
Length
The longer side of a rectangle.
Width
The shorter side of a rectangle.
Worked Examples
Find the area of a rectangle that is 8 cm long and 5 cm wide.
Step 1: Use the formula: Area = Length × Width
Step 2: Area = 8 cm × 5 cm = 40
Answer: Area = 40 cm²
A square has sides of 7 m. What is its area?
Step 1: A square is a special rectangle where length = width.
Step 2: Area = 7 m × 7 m = 49
Answer: Area = 49 m²
A rectangle has an area of 36 cm² and a length of 9 cm. What is its width?
Step 1: Area = Length × Width, so Width = Area ÷ Length
Step 2: Width = 36 ÷ 9 = 4
Answer: Width = 4 cm
Knowledge Check
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Key Concepts Summary
- ●Area is the space inside a 2D shape, measured in square units.
- ●Area of a rectangle = Length × Width.
- ●A square is a special rectangle — Area = side × side.
- ●For compound shapes, split into rectangles, find each area, then add.
- ●Always include the correct unit in your answer (cm², m²).