Consider the following proof. What theorem is being proved? Given: Isosceles △ABC with AB¯¯¯¯¯¯¯¯≅BC¯¯¯¯¯¯¯¯ Prove: ∠A≅∠C Statements Reasons 1. Isosceles △ABC with AB¯¯¯¯¯¯¯¯≅BC¯¯¯¯¯¯¯¯ 1. Given 2. BD←→ 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 (1 point) Responses the Triangle Inequality Theorem the Triangle Inequality Theorem the Base Angles Theorem the Base Angles Theorem the Triangle Sum Theorem the Triangle Sum Theorem the Isosceles Triangle Theorem

Answer 1

The theorem being proved in the provided proof is the Base Angles Theorem (also known as the Isosceles Triangle Theorem). This theorem states that in an isosceles triangle, the angles opposite the equal sides are congruent. In this case, the proof demonstrates that in isosceles triangle \( \triangle ABC \) with \( AB \cong BC \), the angles \( \angle A \) and \( \angle C \) are congruent.