11 Plus Circle Geometry Practice | Clear 11+ Maths Help
21 October 2026
Understanding circles in 11 plus maths
Circle geometry is a common topic in the 11+ maths exam. Children are expected to know about the radius, diameter, circumference and area of a circle. Practising these questions helps build confidence for test day.
Key insight: Most 11+ circle questions use simple formulas and clear steps. Encourage your child to remember the difference between radius and diameter.
Key circle facts to remember
The radius is the distance from the centre of the circle to the edge. The diameter is twice the radius. The circumference is the distance all the way around the circle. The area is the space inside the circle.
Formulas to know:
Circumference = π × diameter (or 2 × π × radius)
Area = π × radius × radius
Worked example
A circle has a diameter of 10 cm. What is its circumference?
Step 1: Write the formula. Circumference = π × diameter.
Step 2: Substitute the values. Circumference = π × 10 cm.
Step 3: Use π ≈ 3.14. Circumference = 3.14 × 10 cm.
Step 4: Calculate. 3.14 × 10 = 31.4
The correct answer is 31.4 cm.
Supporting your child with practice
Ask your child to identify the radius and diameter in different questions. Practise using both circumference and area formulas. Encourage careful reading of each question to spot which measurement is needed.
Key insight: Drawing a quick sketch can help children visualise the problem and avoid simple mistakes.
