Find the perimeter of a rectangle using centimetre cubes
31 October 2026
If your child is learning about perimeter, using centimetre cubes can make the idea much clearer. Seeing and counting the cubes helps children understand how the sides of a rectangle add up to make the perimeter.
Worked example
Question: A rectangle is made using centimetre cubes. The rectangle is 4 cubes long and 3 cubes wide. Find the perimeter.
Step 1: Count the cubes along one long side. There are 4 cubes.
Step 2: Count the cubes along one short side. There are 3 cubes.
Step 3: A rectangle has two long sides and two short sides.
Step 4: Add the lengths of all sides: 4 + 4 + 3 + 3
Step 5: 4 + 4 = 8
Step 6: 3 + 3 = 6
Step 7: 8 + 6 = 14
The correct answer is 14 centimetres.
After working through this example, your child will be able to spot the sides of a rectangle and count the cubes to find the perimeter. They can now try similar questions to build confidence with perimeter problems using centimetre cubes.
