Given in the picture are two triangles with common side OM.
L and N are on either side of OM
In triangles OML and OMN, given that
angle L = angle N
and OM is perpendicular to LN.
Hence in these two triangles OML, and OMN we have
OM=OM (reflexive property)
Angle L = angle N(given)
Angle OML = angle OMN (perpendicular)
Thus two angles and one corresponding side are equal
Hence by AAS property the two triangles are congruent.
(since side is not included by the angles)
