What reason can be used to complete this proof?

m∠1=m∠3 because ∠1≅∠3.
m∠1+m∠2=m∠SMQ and m∠2+m∠3=m∠RMT ______________.
m∠1+m∠2=m∠RMT because you can substitute m∠1 for m∠3.
m∠SMQ=m∠RMT by the transitive property of equality.
So, ∠RMT≅∠SMQ.

Given: ∠1≅∠3Prove: ∠RMT≅∠SRQ