1. Circles – Segments and Circumference Circle – The set of all points in a plane a given distance from a given point (the center). Circles are named by their center point. Concentric circles – Circles in the same plane with the same center.

2. Circles – Segments and Circumference Radius – Any segment with endpoints that are the center of a circle and a point on the circle. Chord – A segment with two endpoints on the circle. Diameter – A chord that passes through the center.

3. Circles – Segments and Circumference Pi (  ) – An irrational number that is defined as the ratio of the circumference to the diameter of a circle. (C/d =  ) Circumference – The distance around a circle. Represented by either: C =  d or C = 2  r

4. Example 1-1e Answer: a. Name the circle. b. Name a radius of the circle. c. Name a chord of the circle. d. Name a diameter of the circle. Answer:

5. Example 1-2d Answer: 58 Answer: 12.5 a. If BG = 25, find MG. b. If DM = 29, find DN. Circle M has diameters c. If MF = 8.5, find MG. Answer: 8.5

6. The diameters of, and are 5 inches, 9 inches, and 18 inches respectively. a. Find AC. b. Find EB. Example 1-3e Answer: 6.5 in. Answer: 13.5 in.

7. a. Find C if r = 22 centimeters. b. Find C if d = 3 feet. c. Find d and r to the nearest hundredth if C = 16.8 meters. Example 1-4e Answer:

8. Example 1-5d Answer: C Find the exact circumference of. A B C D