1. Angles Formed by Tangents, Chords, and Secants

2. Tangent: A line that intersects the circle in exactly one point.
PT is a tangent P T A

3. Angle Formed by Tangent and Chord:
The measure of an angle formed by a tangent and a chord intersecting at the point of tangency is one-half the measure of the intercepted arc. P T A

4. Angles Formed by Two Chords In a Circle:
The measure of an angle formed by two chords intersecting in a circle is one-half the sum of the measures of the arcs intercepted by the angle and by its vertical angle. A B C D E

5. 1. If mAC = 30 and mAEC = 55, find mBD.

6. 2. If mAC = 20 and mBD = 100, find mAEC.

7. 3. If mCB = 120 and mAD = 180, find mAED.

8. 4. If mAC = 27 and mDB = 81, find mDEB.

9. 5. If mAC = 20 and mAEC = 70, find mBD.

10. 6. If mBD = 75 and mDEB = 60, find mAC.

11. 7. If mAB = 100 find mABC. A B C D

12. 8. mABC = 75, find mAB. A B C D

13. 9. If mABD = 110, find mAEB. A B C D E

14. 10. If mAEB = 105, find mABD A B C D E