Area of rectangles with shapes: a parent's guide for 11+ maths
21 October 2026
Understanding area for 11+ maths
Calculating area is a key skill for 11+ maths. Children are often asked to find the area of rectangles and more complex shapes made out of rectangles. Knowing these steps helps your child feel confident in tackling area questions.
How to find the area of a rectangle
To work out the area of a rectangle, you need to know its length and width. Area tells you how much space is inside the shape, measured in square units like cm².
Step-by-step example: area of a rectangle
Suppose you have a rectangle with a length of 5 cm and a width of 4 cm.
1. Measure the length: 5 cm
2. Measure the width: 4 cm
3. Multiply length by width: 5 cm × 4 cm = 20 cm²
4. The area is 20 cm²
Calculating area of composite shapes
Some shapes are made by joining two or more rectangles. To find the total area, break the shape into rectangles, work out the area of each, then add them together.
Step-by-step example: area of a composite shape
Imagine an L-shaped figure split into two rectangles:
- Rectangle 1: length 6 cm, width 2 cm - Rectangle 2: length 3 cm, width 4 cm
1. Area of Rectangle 1: 6 cm × 2 cm = 12 cm²
2. Area of Rectangle 2: 3 cm × 4 cm = 12 cm²
3. Add both areas: 12 cm² + 12 cm² = 24 cm²
4. The total area is 24 cm²
Tips for supporting your child
Encourage your child to draw lines to split complex shapes into rectangles. Double-check each measurement and calculation, and always include the correct unit (cm² or m²).
Key insight: Breaking down composite shapes into rectangles makes area questions much clearer and helps children solve them step by step.
