1. Measuring Angles and Arcs

2. Angles and Arcs Central angle
Is an angle whose vertex is at the center of a circle
and whose sides are radii

3. Angles and Arcs
Sum of measures of central angles 1 3 2

4. Angles and Arcs An Arc A portion of circle defined by two endpoints R

5. Angles and Arcs R A central angle separates a circle into two arcs Q P
Measures of the arcs are related to the measures of central angles

6. Angles and Arcs A Minor Arc x B C
The shortest arc connecting two endpoints on a circle B
Its measure is less than 180 C

7. Angles and Arcs A Major Arc x B C D
The longest arc connecting two endpoints on a circle B
Its measure is greater than 180 C D

8. Angles and Arcs A Semicircle D 180 B C
Is an arc with endpoints that lies on a diameter B
The measure of a semicircle is 180 C

9. Angles and Arcs F 1 2 H G Two minor arcs are congruent if and only if
their
corresponding central angles are congruent 2 H G

10. Angles and Arcs F
Adjacent arcs H G