The angle should measure
I keep the CAST abbreviation rule in mind when doing these types of questions. Starting from quadrant IV and going counter-clockwise, the letters determine which trigonometric function will turn out positive in each quadrant.
C osine, A ll, S ine, T angent.
So for background information, it makes sense that sin would be positive in the second quadrant.
Now, here's the rule:
If the angle is in quadrant II;
#"180 degrees - reference angle = answer"#
And as an extra, quadrant III:
#"180 degrees + reference angle = answer"#
Finally, quadrant IV:
#"360 degrees - reference angle = answer"#
Hope this helps!
A fellow highschool student.