Answer:
a) 45° cause tan = sin/cos and sin 45 and cos 45 both give square root 2/2
b) 120°
c) sin = -1/2 = -30° or 330° both are same
Use the trig circle which i have included in the answer to better understand trig angles
hope that answers your question
I want to let you know that each angle has sets of coordinates the left number is cos and right is sin. Ex) sin of 30 is 1/2 and cos of 30 is square root 3/2 In case you dont fully understand dont hesitate to comment.
good luck!!