Consider the following proof. What theorem is being proved?
Given: Isosceles △ABC with ¯AB¯≅¯BC¯
Prove: ∠A≅∠C
1. Isosceles △ABC with ¯AB¯≅¯BC¯ 1. Given
2. ←BD→ is the angle bisector of ∠B 2. Construction
3. ∠ABD≅∠CBD 3. Definition of angle bisector
4. ¯BD¯≅¯BD¯ 4. Reflexive property of congruence
5. △ABD≅△CBD 5. SAS Congruence Theorem
6. ∠A≅∠C 6. CPCTC Theorem
the Triangle Inequality Theorem
the Base Angles Theorem
the Triangle Angle Sum Theorem
the Isosceles Triangle Theorem