# CT3: Angles in the same segment

- Author:
- Tim Devereux

- Topic:
- Angles

## Angles in the same segment

Third circle theorem:
Compare the sizes of angles α & β, as
you use the cursor to move point C or D around the circumference.
It doesn't change either angle β- they stay the same!
What is the effect of moving point E?
And finally, what happens when you move point B?