1. C HORDS, S ECANTS, AND T ANGENTS 10.1 & 10.3

2. S ECANT A secant is a line that intersects a circle in two points. A tangent is a line that intersects the circle in exactly one point. T ANGENT

3. C HORDS, S ECANTS, AND T ANGENTS Secant Chord Tangent

4. C OMMON T ANGENTS A line, ray, or segment that is tangent to two coplanar circles is called a common tangent.

5. T HEOREM The tangent of a circle is perpendicular to radius at the point of tangency.

6. U SING T ANGENT L INES

7. T HEOREM Tangent segments from a common external point are congruent.

9. T HEOREM In the same circle, or in congruent circles, two minor arcs are congruent if and only if their corresponding chords are congruent.

10. T HEOREM If one chord is a perpendicular bisector of another chord, then the first chord is a diameter.

11. T HEOREM 10.5 If a diameter of a circle is perpendicular to a chord, then the diameter bisects the chord and its arc.

12. W HAT IS THE MEASURE OF A RC CD IN THE FIGURE BELOW ?

13. T HEOREM In the same circle, or in congruent circles, two chords are congruent if and only if they are equidistant from the center.

14. W HAT IS THE VALUE OF X FOR THE CIRCLE BELOW ?