A line that is tangent to the circle is a line that touches (intersects) the circle at exactly one point. That's it - no more, no less, only one. [br][br]A tangent to Circle A has been created in the diagram below. Move the the [b]point of tangency[/b] (the point where the line touches the circle) around the circle and pay close attention to the measure of [math]\angle ABC[/math] as you move it around. This is your first important property of tangent lines.
Using your best and most specific vocabulary, how would you describe the property that is demonstrated in the diagram above?[br][br][b]Note for all typed-in answers[/b]: If your answer shows as incorrect from the program, make sure to compare it to the official answer. Your answer may be very close and a good answer, but the computer will only mark it as "correct" if it is exactly the same.
The tangent to a circle is always perpendicular to the radius at the point of tangency.
Use the diagram below to investigate what happens when two tangents from the same circle intersect. [br][br]In this diagram, you can move the intersection point (D) and point B. Pay attention to the segments whose measures are showing as you change the circle and/or the tangents.
Summarize what you notice about what happens when two tangent lines from the same circle intersect.
When two tangent lines from the same circle intersect, the segments from the point of intersection to the point of tangency will be congruent to each other.