1. CHORDS, SECANTS, & TANGENTS (ANGLE MEASURES) 9.3.3.8 Know and apply properties of a circle to solve problems and logically justify results.

2. Guiding Question: How do I measure intersecting lines in & out of a circle? Lesson Obj: IWBAT know the properties of a circle and solve problems using them. Vocabulary Chords Secants Tangents Major/Minor Arc

3. Guiding Question: How do I measure intersecting lines in & out of a circle? Chords: Any segment with 2 endpts on the circle. Secant: A line passing through a circle Tangent: A line crossing a circle at 1 pt. called a pt. of tangency.

4. Guiding Question: How do I measure intersecting lines in & out of a circle? Recall that a central angle measure is congruent to its arc. An inscribed angle is made by 2 chords with a same endpoint.

5. Guiding Question: How do I measure intersecting lines in & out of a circle? What is the angle measure of x? How big is the intercepted arc?

6. Guiding Question: How do I measure intersecting lines in & out of a circle? If 2 (or more) inscribed angles intercept the same arc, they are congruent! What if I have intersecting chords? How could I find the measure of angles 1 and 2? What kind of angles are they?

7. Guiding Question: How do I measure intersecting lines in & out of a circle?

9. For this it will be half of 170What is the measure of k?

10. Guiding Question: How do I measure intersecting lines in & out of a circle? Summary: Inscribed Angles: Half of central angle intercepting same arc Intersecting chords: Add up the intercepted arcs and divide by 2 2 secants: Big arc – little arc, then divide by 2 1 tangent & 1 secant/chord – half of intercepted arc.

11. Guiding Question: How do I measure intersecting lines in & out of a circle? Assignment: Worksheet