A [color=#ff0000]cyclic quadrilateral[/color] is a 4 sided figure inscribed in a circle.[br][br]Each vertex lies on the circle. [br][br]There are special angle relationships in this type of figure.
Move the points around. Don't let the line segments cross.[br][br][br]Look at the green pair. Look at the red pair. [br][br]The green pair of angles A and C have what relationship?