1. Entry Task

2. 10-6 Circles and Arcs

3. What is a circle? Circle The set of all points in a plane that are the same distance from a given point (this point is called the center of the circle).

4. Terms related to circles Radius A segment from the center of a circle to a point on the circle. Diameter A segment with both endpoints on the circle AND passes through the center. Congruent Circles Two or more circles with equal radii (plural for radius). P Q T

5. Arcs of Circles Arcs –Minor Arc Measure less than 180 –Major Arc Measure greater than 180 –Semicircle Measure exactly 180 Central Angles Angles formed by radii of a circle.

6. Arc Measure The measure of a minor arc is equal to the measure of its corresponding central angle. P A B 125 o

7. Circumference

8. Arc Length 5 in A B X Y

9. Concentric Circles Two or more coplanar circles that share the same center point. R S

10. Homework Assignment Page 654 (9-44 all)