
Jon S. answered 04/23/20
Patient and Knowledgeable Math and English Tutor
The sine function is positive in quadrants I and II, or between 0 and π, so O must lie within those limits.
Sin O is equal to 1/2 when the reference angle is π/6, which occurs in the first quadrant when O = π/6 and in the second quadrant when O = 5π/6.