PROOF: Given isosceles  △ABC  with  AB¯¯¯¯¯¯¯¯≅BC¯¯¯¯¯¯¯¯ , I can construct  BD←→ , the angle bisector of  ∠B . Then, by the definition of an angle bisector, I know that  ∠ABD≅∠CBD . I also know that line segments are congruent to themselves, so  BD¯¯¯¯¯¯¯¯≅BD¯¯¯¯¯¯¯¯  by the reflexive property of congruence. I now have two pairs of sides and an included angle that are congruent, so I know that  △ABD≅△CBD  by the SAS Congruence Theorem.What statement should be placed at the end of the proof?(1 point)ResponsesFinally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so AB¯¯¯¯¯¯¯¯≅BC¯¯¯¯¯¯¯¯.  Finally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so  Modifying above upper A upper B with bar congruent to Modifying above upper B upper C with bar .Finally, ∠A≅∠C by the Base Angles Theorem.Finally,  angle upper A congruent to angle upper C by the Base Angles Theorem. Finally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so ∠A≅∠B. Finally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so  angle upper A congruent to angle upper B .Finally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so ∠A≅∠C.

1 answer

The correct statement to place at the end of the proof is:

"Finally, corresponding parts of congruent triangles are congruent by the CPCTC Theorem, so ∠A≅∠C by the Base Angles Theorem."

This statement correctly concludes the proof by relating the angles of the congruent triangles formed (△ABD and △CBD) to the angles ∠A and ∠C in the isosceles triangle △ABC, reinforcing the property that the base angles of an isosceles triangle are congruent.