​Angles in the Exterior of a Circle and Arc Measures

About Geometry Worksheet Assignment 10.13:                 

 

Assignment 10.13 is an introduction to the theorem about the measures of angles with a vertex at the intersection of secants or tangents in the exterior of a circle and the measures of their intercepted arcs.

 

Prerequisite Skills:  Identify arcs intercepted by lines intersecting a circle (Assignment 10.10).  Solve algebraic equations with one variable.

 

Theorem:  The measure of an angle with vertex at the intersection of secants or tangents in the exterior of a circle is one-half the difference of the measures

                        of the arcs intercepted by the angles.