Inscribed Quadrilateral
1. Move the vertices of the quadrilateral around and look for a pattern between the opposite angles of the inscribed quadrilateral (angle C and angle E, angle D and angle F). 
2. Once you think you know the pattern, uncheck the "Show measure of angle E and angle F" box. 
3. Change the measure of angles C and D. 
4. Calculate the measure of angle E and the measure of angle F. 
5. Then click the box to check your solutions. 
The opposite angle of an inscribed quadrilateral are always _______________.