1. Section 4.1

2. Radian and Degree Measure The angles in Quadrant I are between 0 and 90 degrees. The angles in Quadrant II are between 90 and 180 degrees. The angles in Quadrant III are between 180 and 270 degrees. The angles in Quadrant IV are between 270 and 360 degrees.

3. Radian and Degree Measure Positive angles go counterclockwise. Negative angles go clockwise. Quadrant I is between 0 and pi/2 Quadrant II is pi/2 and pi Quadrant III is between pi and (3pi)/2 Quadrant IV is between (3pi)/2 and 2pi

4. Radian and Degree Measure To convert from degrees to radians you multiply by (pi)/180 To convert from radians to degrees you multiply by 180/pi Coterminal Angles: add or subtract 360 degrees Add or subtract 2pi

5. Radian and Degree Measure Complement: 90 degrees minus the angle Pi/2 minus the angle Supplement: 180 degrees minus the angle Pi minus the angle

6. Radian and Degree Measure Arc Length: s = r (theta) Theta must be in radians.