[tex]\begin{gathered} WY\cong XZ\text{ (Given)} \\ WY=XZ(\text{Segment Addition Postulate)} \\ WX+XZ=WZ,WY+YZ=WZ(Substitution) \\ XZ+YZ=WZ(\text{Segment addition Postulate)} \\ WX+XZ=XZ+YZ(\text{Def of Congruence)} \\ WX=YZ(\text{Substitution)} \\ WX\cong WZ(Def\text{ of Congruence)} \end{gathered}[/tex]
