1. Answers to Homework CE: 1) a) 2 b) 2 c) 2 d) 2 e) 1 f) 0 2) a) 2 b) 1 c)-f) 0 3. a) B b) E Written Ex: 2) 2√34 4) 15 6) 12 8) a) 72 b) 18 c) 144

2. 9-3 Arcs and Central Angles

3. Arcs Minor Arc = Less than half a circle Major Arc = More than half a circle Semicircle = Arc whose points are on the diameter AP C B Circle = 360° < 180° > 180° = 180°

4. Postulate The measure of the arc formed by 2 adjacent arcs is the sum of the measures of the arcs. – What postulate does this remind you of??? – Like angle addition/segment addition postulates AP C B

5. Central Angle Angle created at the center of a circle using two radii AP B Measure of a minor arc = Measure of it’s central angle

6. Examples 30° 120° 40° 30° 40° 120°

7. Example Find angle 1 for each circle 1 1 1 40 225 130 30 360 – (225 + 40) 95 180 – 30 150 180 – 130 50

8. TWAP—(it’s a thinker! Clue: circle) Find x A 2X-14 2X 3X+10 3X 4X E D C B 4x + 3x + 2x – 14 + 2x + 3x + 10 = 360 X = 26

9. Example At 10 o’clock the hands of a clock form an angle of what degree? How many degrees is each hour? 360/12 = 30 10:00 is 60 degrees

10. T.O.O. on whiteboards!!! 1. Find the measure of the angle when the hands of a clock are at 5:00. Answer:150 degrees 2. Find x. x = 130 x 230

11. Homework Page 341 Classroom #2-13, Written # 1-8