Answer:
1. ∠1 ≅ 6 : Given
2. ∠3 ≅ ∠ 4 : Vertical Angles Congruence Property
3. ∠2 ≅ ∠5 : Corollary III of Theorem 19 : If two angles of two triangles are congruent, then the third angle of both triangles are congruent.
Step-by-step explanation: For ∠3 ≅ ∠4, the angles are in a diagonal placement, meaning they are vertical angles. Vertical angles are always congruent.
Lookimg at one of the problems you posted earlier, the Corollary III of Theorem 19 given, states that if two angles are congruent in both triangles, then the third angle is congruent in both triangles. Since we have 2 angles already congruent to 2 other angles, ∠2 and ∠5 must be congruent.
Hope this helped!