Not true either. Firstly, your calculator will only give you the smallest value of the angle. Sine is positive between 0 - 180 degrees and hence this occurs. Thus, your diagram is very important in dropping you a hint whether beta is a acute or obtuse angle.
If I use your qn as an example, if beta is an acute angle, the total angle added up will not be 180 degrees which a triangle cannot be formed since x is an acute angle. Thus, by inspection, by logic, beta angle cannot be acute. It must be obtuse. Therefore, your diagram is important as you can see. It is gd that u have drawn the diagram in such a way that x is an acute angle instead of well obtuse angle.
If the qn states that x is an obtuse angle, you will have to draw your diagram differently, drawing in such a way that x is an obtuse angle.
