Theangleatthecentreistwicetheangleatthe

circumference

Anglesinthesamesegement areequal

Theangleinasemicircleis90

degrees

Oppositeanglesinacyclicquadrilateraladdupto180

degrees

Theperpendicular fromthecentre tothechord

bisectsthechord

Theanglebetweenatangent andaradius

is90degrees

Tangentsfromapointoutsideacircleareequalinlength

Alternate segmenttheorem