- CirclesParts of a CircleCircle Theorem 5 - Radius to a TangentCircle Theorem 7 - Tangents from a Point to a Circle IITangent Chord Investigation & ConjectureIntersecting Chords Investigation & ConjectureAngle in a Semi-CircleCircle Theorem 3 - Angles in the Same SegmentIntersecting Secants Investigation & ConjectureCircle Theorem 1 - Angle at the CentreCyclic QuadrilateralLengths of Segments formed by Intersecting SecantsLengths of Segments formed by Intersecting ChordsCircle Geometry - Intersecting Chords