1. Radians and Angles

2. Angle-formed by rotating a ray about its endpoint (vertex) Initial Side Starting position Terminal Side Ending position Standard Position Initial side on positive x-axis and the vertex is on the origin

3. Angle describes the amount and direction of rotation 120°–210° Positive Angle- rotates counter-clockwise (CCW) Negative Angle- rotates clockwise (CW)

4. 1 Radian = measure of central angle, , that intercepts the arc that has the same length as the radius of the circle

5. Calculate the number of radians in one full circle: C= 0  3.14 0, 2  0, 6.28

6. Coterminal Angles: Two angles with the same initial and terminal sides Find a positive coterminal angle to 20º Find 2 coterminal angles to Find a negative coterminal angle to 20º

7. Complementary Angles: Two angles whose sum is 90  Supplementary Angles: Two angles whose sum is 180 

8. To convert from degrees radians, multiply by To convert from radians degrees, multiply by Convert to radians:

9. To convert from degrees radians, multiply by To convert from radians degrees, multiply by Convert to degrees: