Proving Circle Theorems encourages students to deepen their understanding of geometric relationships within circles. Here are all the circle theorems your learners need to know and be able to prove at GCSE in one place. Pupils will use algebra alongside known angle and line facts to prove: the angle at the centre is twice that at the circumference, opposite angles in cyclic quadrilaterals are supplementary, the angle in a semicircle is 90°, angles in the same segment are equal, the alternate segment theorem and that tangents that meet at the same point are equal in length.

In our selection of resources you can also find dedicated worksheets with guided proofs of the individual theorems.