Students are often unsure why angles in the same segment of a circle have to be equal. Colin Foster explains how to make it ...

When calculating angles using a circle theorem, always state which theorem applies. It may not be possible to calculate the missing angle immediately. It may be necessary to calculate another ...

Circle theorems - Higher - AQA Circles have different angle properties described by different circle theorems. Circle theorems are used in geometric proofs and to calculate angles.