- Circle Theorems for CIE IGCSE Mathematics
- Angles in a semi-circle
- Angle between tangent and radius
- Angle at the centre and angle at the circumference
- Angles in the same segment
- Angles in opposite segments
- Opposite angles in cyclic quadrilaterals
- Distance of equal chords from the centre
- Perpendicular bisector of a chord
- External tangents from a point outside the circle
- Angles in alternate segments
- Chords intersecting inside the circle
- Chords intersecting outside the circle
- Angle between extended chord and tangent