need help

[eobmtd]

given: AC ll XZ, YA bisects <XYB, and BZ bisects <YBC

Prove AY ll BZ



-------A-------------------B-----------------------C



--X-----------Y----------------------Z--------------

 

[pka]

Surely from all that you can get congruent alternate interior angles.
Use line YB as the transversal.

 

[eobmtd]

ya, sorry.....I have that

it's 2 parallel lines cut by the by the BY transversal, therefor the bisectors of alternate interior angles are parallel.


what do I write to prove AY ll BZ?