Central Angle, Inscribed Angle, Circular Segment Angle and Arc

Move points A, B or C and compare the angles. What can you notice?

Change the "steps" selector and observe the proof steps. Did you understand the proof? In case you did not understand the property of the external angle click here and review. Go back to step 0. Move point C downwards. Notice the proof steps. Did you understand the proof? Go back to step 0. Move point C upwards. Notice the proof steps. Did you understand the proof?

Change the position of point C and compare the circular segment angles and the central angle. What can you notice?

What is the measure of the angle AEB? and of the angle ADB? Why?