1. Secant-Secant Angles
Interior Secant Angle – An angle formed when two secants intersect inside a circle.
Theorem 10.13
A secant angle whose vertex is inside a circle is equal in measure to half the sum of the arcs intercepted by it and its vertical angle.

2. Find if and
Answer: 138
Example 6-1d

3. Secant-Secant Angles
Exterior Secant Angle – An angle formed when two secants intersect outside a circle.
Theorem 10.14
A secant angle whose vertex is outside a circle is equal in measure to half the difference of its larger and smaller intercepted arcs.

4. Find x.
Answer: 111
Example 6-3c

5. Tangent-Tangent Angles
Tangent-Tangent Angle – An angle formed when two tangents intersect in the exterior of a circle.
Theorem 10.14
A tangent-tangent angle whose vertex is outside a circle is equal in measure to half the difference of its larger and smaller intercepted arcs.

6. PARKS Two sides of a fence to be built around a circular garden in a park are shown. Use the figure to determine the measure of
Answer: 75
Example 6-4c