Perimeter Word Problem: Triangle
22 October 2026
When your child is faced with a perimeter word problem involving a triangle, it helps to break the question down into simple steps. Remind them that the perimeter is just the total distance around the shape.
Worked example
A triangle has sides measuring 5 cm, 7 cm, and 8 cm. What is the perimeter of the triangle?
Add the lengths of all three sides: 5 cm + 7 cm + 8 cm.
5 + 7 = 12.
12 + 8 = 20.
The correct answer is 20 cm.
After working through this example, your child can spot that perimeter questions for triangles always involve adding the three side lengths together. Practising similar problems will help them feel confident with this type of 11+ maths question.
