Question

how we prove the statements with 2 column proofs?

Answer 1

so as your given angle 4. angle 5 and angle 5 are alternate angles! so from that angle 4=5
and angle 7 equals angle 6 due to opposite angles!
so if it's given that angle 4 is equal to 7
and we found out that 4=5 6=7
we can definitely 5=6