Proof:
Consider [tex]\triangle WXZ, \triangle YZX:[/tex]
[tex]\overline W\overline X = \overline Y\overline Z[/tex] (given)
[tex]\angle WXZ = \angle YZX[/tex] (alternate angles are equal, [tex]\overline W\overline X\parallel \overline Y\overline Z[/tex])
[tex]\overline Z \overline X[/tex] is a common side
∴ [tex]\triangle WXZ \cong \triangle YZX[/tex] (SAS)
Hope this helps :)
