Circle Theorems and Parallel Line Angles

What circle theorem is this?

The angle at the centre of a circle is twice the angle at the circumference

What circle theorem is this?

Angles at the circumference in the same segment are equal

What circle theorem is this?

Opposite angles in a cyclic quadrilateral add up to 180

What circle theorem is this?

The angle at the circumference in a semicircle is a right angle

What circle theorem is this?

The angle between a tangent and a radius is 90

What circle theorem is this?

Tangents which meet at the same point are equal in length

What circle theorem is this?

The perpendicular from the centre of a circle to a chord bisects the chord

What circle theorem is this?

The angle between a tangent and a chord is equal to the angle in the alternate segment

What parallel line angle rule is this?

Corresponding angles are equal - F shape

What parallel line angle rule is this?

Co-interior angles add to 180 - C shape

What parallel line angle rule is this?

Alternate angles are equal - Z shape

What parallel line angle rule is this?

Vertically opposite angles are equal - X shape