Warm up

1. Warm up • 2 – 18 evens only. • This will be graded in 10 minutes. • 2.79 • 27.93 • 61.78 • 138.4 • 7.16 • 309.4° • 107 ° • 16. 1.6 ° • 18. 72.5 °

2. 9.2 Tangents and Secants Tangents and secants are LINES. A tangent line intersects the circle at exactly ONE point. A secant line intersects the circle at exactly TWO points.

3. A little extra information • The word tangent comes from the Latin word meaning to touch • The word secant comes from the Latin word meaning to cut.

4. Important Theorems • Tangent Theorem: • If a line is tangent to a circle, then the line is perpendicular to a radius of the circle drawn to the point of tangency. The line AB is tangent to circle C at B. How could we prove that segment CB and line AB are perpendicular?

5. Converse of the Tangent Theorem • Go waaaayyy back… how do we get a converse statement? • What would be the Converse of the Tangent Theorem? • If a line is perpendicular to a radius of a circle at its endpoint on the circle, then the line is tangent to the circle.

6. Radius and Chord Theorem • A radius that is perpendicular to the chord of a circle bisects the chord. QR = 3 What is the measure of RS? XR = 7 and WR = 2 Find the missing measures of the remaining segments. RZ = RY = XW = WZ = XZ = 7 7 6.7 6.7 13.4

7. Let’s Practice I need 2 volunteers to hand out whiteboards and markers.

9. Your assignment • Pg 577; 10-13, 19-26 • Pg 846, Lesson 9.2, 1-6