1. 10-3 Arcs and Chords

2. Arcs and Chords
In a circle (or 2 congruent circles) two minor arcs are congruent if and only if their corresponding chords are congruent. A B C D

3. Inscribed and Circumscribed Polygons
If all the vertices of a polygon lie on a circle then the polygon is inscribed in the circle
The circle is circumscribed about the polygon because it contains the vertices B C A E D

4. Diameters and Chords
If a diameter (or radius) is perpendicular to a chord then it bisects the chord and its arc B C T V U A

5. Example:
Circle W has radius 10 cm. Radius WL is perpendicular to chord HK and HK is 16 cm.
If mHL = 53, find mMK
Find JL M W J H K L

6. Chords equidistant from the center
In a circle, 2 chords are congruent if and only if they are equidistant from the center
Example: EF and GH are equidistant form the center. If the radius is 15 and EF=24, Find PR and RH F Q E H P R G

7. Example: Radius of N is 18, NK=9, mDE=120 Find m<HNE Find HN
Find HE
Find mGE Y K N X D H E G