Drag the green dots around to see the theorems at work.

THEOREM: If a line is tangent to a circle, it is perpendicular to the radius drawn to the point of tangency.

(2)

A) Describe this theorem in your own words.

THEOREM: The tangent chord angle is half the measure of the intercepted arc.

(3)

A) What is the measure of the intercepted arc if the tangent-chord angle is 180?
B) What is the measure of the tangent-chord angle if the intercepted arc is 180?
C) If the tangent chord angle is T, and the intercepted arc is A, what is the relationship between T and A? (State the equation)
D) Describe this theorem in your own words.