You can put this solution on YOUR website! What would be the non-negative obtuse angle for Q if its sin is square root 3 over 2?
-----
In the 1st Quadrant that angle would be 60 degrees.
In the 2nd Quadrant it would be 180-60 = 120 degree.
---
Obtuse is greater than 90 so I guess they want 120 degrees.
Cheers,
Stan H.