Lines normal to one another

About lines that are normal to one another
  • If one line is normal to another, then it is at right angles.
  • In geometry, a normal (or the normal) refers to a line drawn perpendicular to and intersecting another line, plane or surface.
  • In the field of optics, the normal is a line drawn on a ray-tracing diagram perpendicular to (at 900 to), the boundary between two media.
  • If the boundary between two media is curved then the normal is drawn at a tangent to the boundary.