Can anyone help me with this geometry proof

m∠3 = 57° → proved down

Step-by-step explanation:

The given is:

We want to prove that m∠3 = 57°

∵   // and is the transversal → given

∴ m∠1 = m∠2 → corresponding angles

∵ m∠1 = 123° → given

∴ m∠2 = 123° → equality of two corresponding angles

∵ // and is the transversal → given

∴ m∠2 + m∠3 = 180° → interior supplementary angles  

∵ m∠2 = 123° → proved

∴ 123 + m∠3 = 180 → subtract 123 from both sides

∴ m∠3 = 57° → inverse addition property