http://www.ck12.org Chapter 9. Circles
9.2 Tangent Lines
Here you’ll learn two theorems about tangent lines and how to apply them.
What if a line were drawn outside a circle that appeared to touch the circle at only one point? How could you
determine if that line were actually a tangent? After completing this Concept, you’ll be able to apply theorems to
solve tangent problems like this one.
Watch This
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter9TangentLinesA
MEDIA
Click image to the left for more content.James Sousa:TangentLines to a Circle
MEDIA
Click image to the left for more content.James Sousa:TangentLines to a Circle Example Problems
Guidance
The tangent line and the radius drawn to the point of tangency have a unique relationship. Let’s investigate it here.
Investigation: Tangent Line and Radius Property
Tools needed: compass, ruler, pencil, paper, protractor
- Using your compass, draw a circle. Locate the center and draw a radius. Label the radiusAB, withAas the
center.