Angles and Angle Measures

1) -21pi/8 = -21pi/8 + 4pi = 11pi/8. 11pi/8 is > than pi or 180 degrees, but is < 3pi/2 or 270 degrees, so the terminal ray lies in Quadrant III.

-5pi/9 = -5pi/9 + 2pi (coterminal) = 13pi/9. 13pi/9 is greater than pi or 180 degrees, but is less than 3pi/2 = 13.5pi/9 or 270 degrees, so this terminal ray also lies in QUadrant III.

3) 5pi/6 is > pi/2 or 90 degrees, but < pi or 180 degrees, so 5pi/6 lies in quadrant two.

4) 35pi/4 = 35pi/4 - 8pi = 35pi/4 - 32pi/4 = 3pi/4. 3pi/4 = 135 degrees, which is located in Quadrant II.