- CirclesParts of a CircleParts of a CircleVideo Notes - Circles and CircumferenceVideo Notes - Measuring Angles and ArcsCentral and Inscribed AnglesInscribed Angle in a SemicircleRight Angles = Inscribed Angles in a SemicircleInscribed AnglesInscribed Angles Cutting Off the Same ArcInscribed Angles Cutting Off the Same ArcAngles of a Quadrilateral Inscribed in a CircleTangents to a CircleCircle Tangent-Radius AnglePerpendicular Bisector of a Chord