1. 10.2 Arc Measures

2. The two points are called endpoints
Arc
Two points on the circle and a continuous (unbroken) part of the circle between the two points
The two points are called endpoints

3. Semicircle
An arc of a circle whose endpoints are the endpoints of a diameter; HALF of a circle
Minor Arc
An arc of a circle that is smaller than a semicircle
Major Arc
An arc of a circle that is larger than a semicircle

4. Semicircles & Major arcs uses 3 letters
Naming an Arc
arc AB is written as
Minor arcs use 2 letters
Semicircles & Major arcs uses 3 letters

6. Central Angle
A central angle has its vertex at the center of the circle.
Central Angles
Not Central Angles

7. Has the same measure as the central angle that intercepts it
Arcs
Two points on the circle and a continuous (unbroken) part of the circle between the two points.
Measured in Degrees –
360 around the circle
Has the same measure as the central angle that intercepts it

10. Congruent Chords Conjecture
Given: Marked Info Prove: The arcs intercepted by the chords are congruent Hint: Do not use vertical angles. (Why?)

11. Two arcs have equal measures if and only if their circles are congruent and their central angles are congruent.