Can anyone help me? i have no idea what to do


Answer:
In geometric optics, the angle of incidence is the angle between a ray incident on a surface and the line perpendicular to the surface at the point of incidence, called the normal. The ray can be formed by any wave: optical, acoustic, microwave, X-ray and so on.
Explanation:
: the angle between a reflected ray and the normal drawn at the point of incidence to a reflecting surface.