please help me i dont understand this question at all

Question

   A ray of light strikes a mirror. The angle formed by the incident ray and the reflected ray measures 90 degrees. What are the measurements of the angle of incidence and the angle of reflection?

Answer 1

The Law of Reflection tells us that the angle of incidence of a ray of light equals the angle of reflection of the ray.  See the following link:

 

http://scienceworld.wolfram.com/physics/LawofReflection.html

 

Let θ = the angle of incidence.  By the Law of Reflection, the angle of reflection is also θ.

 

2θ = 90^o

 

θ = 90^o/2

 

θ = 45^o