Edexcel GCSE Higher Maths - Circle Theorems

The alternate segment theorem is the angle that lies between a tangent and a chord is equal to the angle subtended by the same chord in the alternate segment.

The angle at the centre is twice the angle at the circumference.

Angles in the same segment are equal.

The angle in a semicircle is 90 degrees.

The perpendicular from the centre of a circle to a chord bisects the chord (splits the chord into two equal parts).

The angle between a tangent and a radius is 90 degrees. Tangents which meet at the same point are equal in length.

The opposite angles in a cyclic quadrilateral total 180 degrees.

The alternate segment theorem is the angle that lies between a tangent and a chord is equal to the angle subtended by the same chord in the alternate segment.

The angle at the centre is twice the angle at the circumference.

Angles in the same segment are equal.

The angle in a semicircle is 90 degrees.

The perpendicular from the centre of a circle to a chord bisects the chord (splits the chord into two equal parts).

The angle between a tangent and a radius is 90 degrees. Tangents which meet at the same point are equal in length.

The opposite angles in a cyclic quadrilateral total 180 degrees.