MathsYears 10–11Geometry - Properties of Shapes
Circle theorems (basic)
Apply basic circle theorems: angle at centre, angle in semicircle, tangent perpendicular to radius
What you'll learn
- 1
Imagine a pizza 🍕 with a dot right in the middle. A line from the dot to the crust is the radius — like a spoke on a bike wheel.
- 2
How many radius lines fit across the diameter?
- 3
Drag the dot to make a radius that touches the circle edge.
- 4
The angle at the centre is twice the angle at the edge — let's prove it!
- 5
If the angle at the centre is 80°, what is the angle at the edge?
- 6
Use the protractor to measure the edge angle when the centre angle is 120°.
- 7
What is the angle at the centre if the edge angle is 35°?
Practise Circle theorems (basic) with Whizlo
Free AI-tutored lessons, unlimited practice questions, and progress tracking for ages 14–16. Aligned to the UK National Curriculum.