Properties of Cyclic Quadrilaterals

Enrichment #1 - Explore the quadrilateral that has been inscribed in a circle. Make a conjecture about the angles in the quadrilateral. Attempt to prove your conjecture.
Hints: 1. Drag one of the vertices of the quadrilateral. What do you notice that changes? 2. Drag the the vertices to create the following shapes. - Parallelogram, Rectangle, Square, Rhombus. What happens to the intersection point of the diagonals? Next - construct a general quadrilateral that is NOT inscribed in a circle. Does the property you noticed about the angle measures still hold true?