The circle theorems

Circles have different angle properties described by different circle theorems. Circle theorems are used in geometric proofs and to calculate angles. Circles have different angle properties, described by theorems. There are seven circle theorems. An important word that is used in circle theorems is subtend, meaning an angle created by an object at a given point.

1) Angles at the centre and circumference

2) Angles in the same segment

3) Cyclic quadrilaterals

4) Angles in a semicircle

5) Tangents

6) Chords

7) The alternate segment theorem

Exercise 1 | Answer Keys
Exercise 2 | Answer Keys

Circle Theoremsexam-styled questions (PDF)