Coterminal Angles

Question

The coterminal angle θ for 2121º such that 0º≤θ≤360º is 

The coterminal angle θ for 2121º such that -360º≤θ≤0º is 

The reference angle θ for 2121º is

Answer 1

(a) 321 degree. Calculated as 2121 - 360*5. You subtract 360 as many times as you need to till you get a value between 0 and 360.

(b) - 39 degree. Calculated as 2121 - 360*6. You subtract 360 as many times as you need to till you get a value between -360 and 0.

(c) Reference angle for angle in Quadrant 4 is = 360 - angle

=360-321 = 39 degree