Answer:
Step-by-step explanation:
1. Angle 3 is congruent to Angle 4 1. Given
2. Angle 3 is linear pair with Angle BAC 2. Definition of linear pair
3. Angle 4 is linear pair with Angle BCA 3. Definition of linear pair
4. Angle BAC is congruent to Angle BCA 4. Both are linear pairs to congruent angles
5. Triangle BAC is isosceles 5. Triangle has 2 congruent angles
6. AB is congruent to BC 6. Opposite side of congruent angles are congruent
