We start at what it gives us, so 2 matches "Given".
So, 3 matches "Supplements to - angles".
From what we see that 1 matches "Exterior sides in oppposite rays".
We can see that 4 matches "Reflexive".
From this we got that 5 matches "ASA", because the triangles are congruent by angle-side-angle.
Because they are congruent, we match 6 with "CPCTE" (Corresponding Parts of Congruent Triangles are Equal).
