1. Circles and Circumference

2. Special Segments in the Circle
Radii
Radius

3. Special Segments in the Circle
Diameter
Chord

4. Special Segments in the CircleB
Diameter
Radius
Chord C P E D

5. Special Segments in the Circle
Radius
A segment with endpoints that are at the center and on the circle
Chord
A segment with endpoints on the circle

6. Special Segments in the Circle
Diameter
chord that passes through the circle’s center and made up of
collinear radii
For a circle that has radius r
and diameter d

7. Circle Pairs
Congruent Circles K H J G

8. Circle Pairs
Tow Circles are Congruent Circles if and only if they have congruent radii

9. Circle Pairs
Concentric Circles C B A

10. Concentric Circles are coplanar circles that have the same center
Circle Pairs
Concentric Circles are coplanar circles that have the same center

11. Circumference r d