Exterior Angle Theorem

1. Create a line segment. Label the endpoints A and B. 2. Place point C any where on segment AB. 3. Create a point D not on AB so that you are able to create the triangle ADB. 4. Measure all interior angles of the triangle. Also measure the exterior angle DCB. 5. Move vertex D around and notice the changing measurements. 6. Notice any relationships specifically between interior angles and the exterior angle.

What relationships do you notice between the exterior angle DCB and the interior angles? Are there specific interior angles that have a relationship with this exterior angle? Are there any conclusions you could draw relating to interior angles and exterior angles?