1. Section 4.1

2.  Trigonometry: the measurement of angles  Standard Position: Angles whose initial side is on the positive x-axis 90 º terminal 180 º 0º initial vertex 270 º

3. 1.) 50º2.) 130º 3.) 260 º 4.) 310º

4. 1.) -50º2.) -180º 3.) -240 º 4.) -300º

5.  Angles that share the same terminal side  Differ by 360º (or a multiple of 360 ie. 720)  Example 4 vs example 1  To find positive and negative coterminal angles- add and subtract 360 º  1.) 210º2.)-180º3.) 400º

6.  Radians are a 2 nd way to measure an angle  Positive and negative radian measures:

12. 1.)2.) 3.) 4.)

13. 1.)2.) 3.) 4.)

14.  Differ by  To find a positive and negative coterminal angle, add and subtract 1.) 2.) 3.)

15.  Degree to radian: Multiply by 1.)2.) 3.)  Radian to degree: Multiply by 1.) 2.) 3.)

16.  Complementary angles- angles whose sum = 90  Supplementary angles- angles whose sum = 180 1.) 45 º 2.) 61 º 3.) 100 º

17.  Arc length- measures a segment (arc) of a circle  must be in radians  1.) 2.)

18. 1.) 2.)