25 points for correct answer stefan is writing a report about the law of reflection. in his report, he says that the angle of incidence is the angle between the surface of the mirror and the incoming ray. do you agree with him? why or why not?

No.  I do not agree with Stefan.  Quite the contrary.  I disagree
with his description of "angle of incidence" as the angle between
the surface of the mirror and the incoming ray. 

The correct description of "angle of incidence" is the angle between
the NORMAL TO the surface of the mirror and the incoming ray. 

Thus, the true angle of incidence is the complement of the angle that
Stefan calculates or measures.