Perimeter is the distance all the way round a shape. Area is the amount of flat space inside it. They are measured in different units — centimetres for perimeter, square centimetres for area — and are easy to mix up.
What your child will learn
- Find the perimeter of a square or rectangle by adding its sides
- Find the area of a square or rectangle by multiplying length by width
- Use the right units: cm or m for perimeter, square cm or square m for area
- Find a missing side when the area is known
Fence or carpet?
A fence goes round the edge of a garden: that is perimeter. A carpet covers the floor: that is area. For a rectangle 6 m long and 4 m wide, the fence is 6 + 4 + 6 + 4 = 20 m, and the carpet is 6 × 4 = 24 square m.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. A square has sides of 5 m. What is its perimeter in m?
- 21
- 10
- 25
- 20
Show answer
Answer: 20. A square has 4 equal sides: 4 × 5 = 20 m.
2. A rectangle is 5 cm long and 2 cm wide. What is its perimeter in cm?
Show answer
Answer: 14. Perimeter is the distance all the way round: 5 + 2 + 5 + 2 = 14 cm.
3. A rectangle is 8 m long and 3 m wide. What is its perimeter in m?
- 24
- 32
- 11
- 22
Show answer
Answer: 22. Perimeter is the distance all the way round: 8 + 3 + 8 + 3 = 22 m.
Tips for grown-ups
- Measure a room together and work out its perimeter and area.
- Draw rectangles on squared paper and count the squares to check the area.