Kyle lays a mirror flat on the floor and aims a laser at the mirror. the laser beam reflects off the mirror and strikes an adjacent wall. the plane of the incident and reflected beams is perpendicular to the wall. the beam from the laser strikes the mirror at a distance a=66.9 cm from the wall. the reflected beam strikes the wall at a height b=37.3 cm above the surface of the mirror. find the angle of incidence θi at which the laser beam strikes the mirror.