Skip to main content
Back
0

KS2 Maths · Measurement · Year 4

Area and perimeter of rectangles

The distance around a shape, and the space inside it.

About 20 minutes

Step 1 · Wonder why it matters

Hook

Fence or grass?

A farmer wants to fence in a field and then plant grass seed inside it. She needs two different measurements: how much fence goes around the edge, and how much seed covers the inside.

The distance around is the perimeter. The space inside is the area.

Step 2 · See it

Picture

See the rectangle

This rectangle is 5 cm long and 3 cm wide. Each small square is 1 cm by 1 cm.

5 cm

3 cm

Perimeter = 16 cm · Area = 15 cm²

Step 3 · Understand how it works

Logic

Two different calculations

Perimeter: add up the lengths of all the sides. For a rectangle, that is length + width + length + width, or 2 × (length + width). It is measured in cm or m.

Area: count the squares inside, or multiply length × width. It is measured in square units such as cm² or m².

Perimeter
The total distance around the outside of a shape.
Area
The amount of flat space a shape covers.
cm²
Square centimetres — the number of 1 cm by 1 cm squares.

Worked example

A rectangle is 7 m long and 4 m wide. Find its perimeter and area.

  1. 1Perimeter: 7 + 4 + 7 + 4 = 22.
  2. 2Area: 7 × 4 = 28.
  3. 3Add the right units to each answer.

Answer: Perimeter = 22 m, area = 28 m²

Step 4 · Have a go

Do

Have a go

You need a ruler, a pencil and squared paper if you have it.

  1. 1Measure a book, a table mat or a tablet. Write its length and width in cm.
  2. 2Work out its perimeter.
  3. 3Work out its area.
  4. 4Challenge: draw two different rectangles that both have an area of 12 cm². Do they have the same perimeter?

Step 5 · Remember it

Recall

Quick quiz

Watch out — some ask for perimeter and some for area.

0 of 4 answered

  1. 1.A rectangle is 6 cm by 2 cm. What is its perimeter?

  2. 2.A rectangle is 6 cm by 2 cm. What is its area?

  3. 3.A square has sides of 5 m. What is its area?

  4. 4.A rectangle has an area of 24 cm² and a length of 8 cm. How wide is it?

Step 6 · Link it to your world

Reflect

Think about it

Builders, gardeners and designers use area and perimeter every day.

If you were painting your bedroom wall, would you need its area or its perimeter? Why?

Saved to your notebook on this device only.

Finished all six steps?

Mark it complete to collect 3 stars. That's the last lesson in this course for now.