angles subtended at the circumference sharing the same arc are equal

bow tie theorem

angle subtended at the centre is double the angle subtended at the circumference

arrow theorem

opposite angles of a cyclic quadrilateral are supplementary

polygon in circle theorem

the angle subtended on the diameter of a circle is always 90

right angled triangle theorem

alternate segment theorem

alternate segment theorem

two tangents from a single point are the same length.

kite theorem