1. Section 10.1
Tangents to Circles

2. Circle
The set of all points on a plane that are equidistant from a given point called the center.

3. Circle
Secant
Center
Tangent
Radius
Chord
Diameter

4. Tangent Circles
Tangent circles are two circles that intersect at exactly one point.

5. Concentric Circles
Two circles with the same center.

6. Common Tangents
A common tangent is a line that is tangent to two circles.
Common Exterior Tangents – The two tangent lines stay on the “outside” of the two circles.
Common Interior Tangents – The two tangent lines go “between”

7. Theorem
A line is tangent to a circle if and only if it is perpendicular to the radius drawn to the point of tangency.

8. Theorem
If two segments from the same exterior point are tangent to a circle, then the segments are congruent.

9. Example

10. Example

11. Homework
Pg 599 #18-41, 46-48