Answer:
D
Explanation:
They just proved that m< 3 =m< 7 and m< 4=m< 8
So if m< 8=m< 5 and m< 7=m< 6
You can plug in m<5 for m< 8 and m<6 for m<7
Therefore:
m<6=m<3
m<5=m<4
Also, the angles that were proved congruent were vertical angles so the theorem they put works