Remark
It is very handy to remember that a line is always equal to itself. In this case, LN = LN will come in very handy.
Givens
LM = PL Given
MN = NP Given
LN = LN Reflexive property. A line is always equal to itself.
These three sides are congruent in one triangle as they are in the second triangle. The triangles are congruent by SSS
