Lenny wrote a paragraph proof of the Perpendicular Bisector Theorem. What mistake did Lenny make in his proof?HK¯¯¯¯¯¯¯¯¯  is a perpendicular bisector of  IJ¯¯¯¯¯¯ , and L is the midpoint of IJ¯¯¯¯¯¯ . M is a point on the perpendicular bisector,  HK¯¯¯¯¯¯¯¯¯ . By the definition of a perpendicular bisector, I know that  IM¯¯¯¯¯¯¯¯≅JM¯¯¯¯¯¯¯¯ . By the definition of a perpendicular bisector, I also know that  ∠MLI  and  ∠MLJ  are right angles.  ∠MLI≅∠MLJ  because of the Right Angle Congruence Theorem. I can also say that  ML¯¯¯¯¯¯¯¯¯≅ML¯¯¯¯¯¯¯¯¯  by the Reflexive Property of Congruence. With this information, I know that  △MLI≅△MLJ  by the SAS Congruence Theorem. Since the triangles are congruent, the CPCTC Theorem allows me to know that  IL¯¯¯¯¯¯≅JL¯¯¯¯¯¯¯ . Knowing that these segments are congruent proves the Perpendicular Bisector Theorem.(1 point)ResponsesThe definition of a perpendicular bisector tells you that IL¯¯¯¯¯¯≅JL¯¯¯¯¯¯¯, not that IM¯¯¯¯¯¯¯¯≅JM¯¯¯¯¯¯¯¯.The definition of a perpendicular bisector tells you that line segment cap i liters is congruent to line segment cap j liters, not that line segment cap i cap m is congruent to line segment cap j cap m.The SAS Congruence Theorem tells you that △MLI≅△JLM, not that △MLI≅△MLJ.The SAS Congruence Theorem tells you that △MLI≅△JLM, not that △MLI≅△MLJ.Lenny did not make a mistake. His proof is correct.Lenny did not make a mistake. His proof is correct.The definition of a perpendicular bisector tells you that∠LMI and ∠LMJ are right angles, not that ∠MLI and ∠MLJ are right angles.The definition of a perpendicular bisector tells you that   ∠LMI and ∠LMJ are right angles, not that    ∠MLI and ∠MLJ are right angles.Skip to navigation

1 answer

Lenny made a mistake in using the wrong angles when stating that they are right angles. The correct angles should be ∠LMI and ∠LMJ, not ∠MLI and ∠MLJ. Therefore, the correct response is:

"The definition of a perpendicular bisector tells you that ∠LMI and ∠LMJ are right angles, not that ∠MLI and ∠MLJ are right angles."