Triangle Properties Practice Questions for 11+ Maths
26 October 2026
Why triangle properties matter
Understanding triangle properties is an essential part of 11+ Maths. Many exam questions ask about angles, types of triangles, and how to use their properties to solve problems.
Practising these skills helps children recognise patterns, spot common question types, and build confidence for the test.
How parents can help
Start by reviewing the main types of triangles: equilateral, isosceles, and scalene. Discuss what makes each one different, such as equal sides or equal angles.
Encourage your child to practise identifying triangle types and calculating missing angles using the rule that the angles in a triangle always add up to 180°.
Work through practice questions together, talking through each step. This supports your child to explain their reasoning and spot mistakes before they become habits.
Key insight: The sum of the angles in any triangle is always 180°. This rule is the foundation for many exam questions about missing angles and triangle types.
Worked example
A triangle has angles of 50° and 60°. What is the size of the third angle?
First, add the two known angles: 50 + 60 = 110.
Next, subtract this total from 180 to find the missing angle: 180 - 110 = 70.
The correct answer is 70°.
Tips for effective practice
Use simple sketches to label sides and angles. Ask your child to explain their thinking out loud.
Mix up questions by including both angle calculations and triangle identification. This helps children apply their knowledge in different ways.
Give regular feedback and revisit mistakes together. This builds understanding and exam confidence.
