Circles Interior Angles

Mr. Smith
Angles, Circle
Manipulate the points on the circle to determine the relationship between the angles formed by chords inside a circle and the measures of the intercepted arcs. mDC refers to the measure of arc DC.
1. What is the average of the two arcs intercepted by the chords DE and BC? 2. How is that average related to the measure of the interior angle formed where the chords intersect?