1. Circles
Chapter 10
Sections 10.1 –10.7

2. Parts of a Circle
Circle F F F
center
Use the center to name a circle.

3. Parts of a Circle chord tangent secant diameter radius
Segments & Lines

4. Radius/diameter radius = ½diameter r = ½ d diameter = 2(radius)
Formulas
Radius/diameter
Circumference
radius = ½diameter
r = ½ d
diameter = 2(radius)
d = 2r
C = 2∏r or C = ∏d

5. Types of Angles Central angle Inscribed angle
- Vertex is on the center.
Inscribed angle
- Vertex is on the circle.

6. Types of Arcs
major arc
minor arc
semicircle M
MNO P MO O N
MON

7. Measure of Arcs & Angles
minor arc = its central angle
major arc = its central angle
68°
360 – 68 = 292
68°
292°

8. Measure of Arcs & Angles
minor arc = its central angle
major arc = its central angle
semicircle = 180
180°

9. Measure of Arcs & Angles
minor arc = its central angle
major arc = its central angle
semicircle = 180
inscribed angle = ½minor arc
34°
68°

10. Arc and Chord RelationshipsB C D
If chords are congruent, then arcs are congruent.
then AB CD

11. If a diameter is perpendicular to a chord, then it bisects the chord.
Arc and Chord Relationships
If a diameter is perpendicular to a chord, then it bisects the chord. A B G H K

12. If a diameter is perpendicular to a chord, then it bisects the arc. A
Arc and Chord Relationships
If a diameter is perpendicular to a chord, then it bisects the arc. A B G H K
AH  BH

13. Arc and Chord Relationships
Two chords are  if and only if they are the same distance from the center. A B C D P O R

14. Tangent Theorem