Lesson 8.6: Tangent Lines
Part I: What is a Tangent Line?
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.
A tangent to Circle A has been created in the diagram below. Move the the point of tangency (the point where the line touches the circle) around the circle and pay close attention to the measure of as you move it around. This diagram models the first important property of tangent lines.
PAUSE AND THINK!
Using your best and most specific vocabulary, how would you describe the property that is demonstrated in the diagram above?
Record your answer in your workbook in Lesson 8.6, part 1c.
Part II: Two Tangents
Use the diagram below to investigate what happens when two tangents from the same circle intersect.
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.
Tangent Property #2
What happens when two lines that are tangent to the same circle intersect?
Record your answer in your workbook in Lesson 8.6, 1d.