Proofs (NF)

Steps

1. Write "Given" facts you will use.
2. Each line: a statement, then the reason in brackets.
3. To prove four points are concyclic, use one of the tests: converse of ∠s in the same segment, opposite angles supplementary, or exterior angle = interior opposite angle.
4. End with the exact statement you were asked to prove.

For the whole topic, read Basic properties of circles: key points, common mistakes and how the DSE tests it.

Other methods in this topic