Chapter 10.5 Notes: Apply Other Angle Relationships in Circles Goal: You will find the measures of angles inside or outside a circle.

How do you find the measure of an inscribed angle? Theorem 10.11: If a tangent and a chord intersect at a point on a circle, then the measure of each angle formed is one half the measure of its intercepted arc.

Ex. 1: Line m is tangent to the circle Ex.1: Line m is tangent to the circle. Find the measure of the red angle or arc. Line m is tangent to the circle. Find x or y. Ex.2: Ex.3:

Intersecting Lines and Circles If two lines intersect a circle, they intersect in three places. Theorem 10.12 Angles Inside the Circle Theorem: If two chords intersect inside a circle, then the measure of each angle is one half the sum of the measures of the arcs intercepted by the angle and its vertical angle.

Ex.4: Find the value of x. Ex.5: Find the value of x.

Theorem 10.13 Angles Outside the Circle Theorem: If a tangent and a secant, two tangents, or two secants intersect outside a circle, then the measure of the angle formed is one half the difference of the measures of the intercepted arcs. Ex.6: Find the value of x.

Find the value of the variable. Ex.7: Ex.8: Ex.9: Ex.10: