2. Learning Target: I can find the measures of central angles and arcs. I can find circumference and arc length.

3. A CIRCLE is the set of all points equidistant from a given point called the center. Circle P P

4. A CENTRAL ANGLE of a circle is an angle with its vertex at the center of the circle. Central angle

5. An arc is a piece of a circle’s circumference. Arc

6. One type of arc, a semicircle, is half of a circle. P A C Semicircle ABC m ABC = 180 B

7. A minor arc is smaller than a semicircle. A major arc is greater than a semicircle.

8. A C D minor arcs E O AC CE DE AD

9. A C D semicircles E O ACE CAD

10. A C D major arcs containing point A E O ACD CEA DEA ADC

11. A C D central angles containing D E O AOD DOE

12. A C D radius E O AO DO EO CO

13. A C D diameter E O AE DC

14. The measure of a central angle is equal to its intercepted arc. 53 o O P R m ROP = 53° m RP = 53°

15. Find the measure of each arc. 1. BC = 32 ° 2. BD = 90 ° 3. ABC = 180 ° 4. AB = 148 ° 1. BC = 2. BD = 3. ABC = 4. AB =

16. The circumference of a circle is the distance around the outside of the circle. or

17. The arc length of a circle is the length of an arc; a piece of the circumference. or

18. Concentric Circles are circles within the same plane (coplanar) that have the same center.