Quadrilateral ABCD is inscribed in circle O.
1. Drag points A, B, C, or D to alter the shape of the quadrilateral. Are the opposite angles always supplementary?
2. Check the box to highlight arcs BAD and BCD. These arcs are intercepted by angles A and C. Is the entire circle highlighted by these arcs? What does that mean about the total measure of these two arcs? Does this change if you adjust points D and B?
3. Now, highlight arcs ABC and CDA. These arcs are intercepted by angles B and D. Is the entire circle highlighted by these arcs? What does that mean about the total measure of these two arcs? Does this change if you adjust points A and C?