proving angles congruent using two column proofs im really stuck

Question

Answer 1

The approach is to prove triangles MNP and ONP are congruent, then <3 and <4 are congruent by corresponding parts of congruent triangles are equal (CPCTE).

To prove MNP and ONP are congruent:

Since given <1 = <2, then MP = OP because the sides opposite congruent base angle are congruent

MN = ON is given

NP = NP by reflexive property.

Therefore MNP and ONP are congruent by SSS and then can state <3 and <4 are congruent by CPCTE.