1. 10.5 Angle Relationships in Circles

2. Open up the file 10.5 Chords and Tangents.
The angle formed by the chord and tangent by moving point c.
Compare the angle formed by the chord and tangent to the arc measure formed by the intersecting chord and tangent.

4. Open the file 10.5 Intersecting Chords.
Adjust the measures of the arcs intersected by the chords by adjusting points C and D.
What do you notice about the measures of the vertical angles formed by the chords compared to the arc measures formed by the chords?