- S4 Properties of CircleAngle at centre twice angle at circumferenceAngles in the same segmentPerpendicular from centre to chord bisects chordEqual chords, equal arcsChords equidistant from centre are equalTest for cyclic quadrilateralOpposite angles, cyclic quadrilateralArcs proportional to angles at centreArcs proportional to angles at circumferenceAngle in alternate segmentConverse of Tangent perpendicular to radiusConverse of angle in alternate segment
