1. §9.2 Angles & Arcs Definitions Naming Conventions Arc: Major Arc: B
Minor Arc:
Semicircle:
Naming Conventions
When naming arcs, we use:
This convention always indicates the ___________ path from A to B.
To name a major arc or semicircle, we thus need ______ letters: B C A

2. Practice: Name the shaded arc in each picture
Practice: Name the shaded arc in each picture. Then tell whether it is a minor arc, major arc, or a semicircle. D B C A

3. Practice: Name the shaded arc in each picture
Practice: Name the shaded arc in each picture. Then tell whether it is a minor arc, major arc, or a semicircle. E H F G

4. Practice: Name the shaded arc in each picture
Practice: Name the shaded arc in each picture. Then tell whether it is a minor arc, major arc, or a semicircle. L N K M J

5. Definitions, Properties, Theorems, & Postulates
Central Angle
Property of Central Angles
Sum of Central Angles Theorem
Arc Addition Postulate A C B

6. Theorem
In the same circle, or in congruent circles, two arcs are congruent if and only if their corresponding central angles are congruent. A B C D

7. More Definitions Definitions Concentric circles
Two circles with the same ________, but different ________.

8. Practice. Find the indicated measure.
140º B C

9. Practice. Find the indicated measure.K
90º L M J
100º

10. Practice. Find the indicated measure.X
105º W Y Z

11. Practice. Find the indicated measure.W R xº J
5xº L T