The angle between the plane and the incident ray is 30 degrees. What is the angle between the plane

The angle between the plane and the incident ray is 30 degrees. What is the angle between the plane of the mirror and the reflected ray?

∠φ = 30 “.
∠γ -?
According to the law of reflection, the angle of incidence ∠α is equal to the angle of reflection ∠β: ∠α = ∠β. Since ∠φ + ∠α = 90 “and ∠γ + ∠β = 90”. ∠φ = ∠γ. ∠γ = 30 “.
Answer: the angle between the plane of the mirror and the reflected beam is ∠γ = 30 “.