Question

Which method and additional information would prove triangle ONP and triangle MNL similar by the AA similarity postulate?

Answer 1

Answer: Choice B

Use a rigid transformation to prove that angle NPO is congruent to angle NLM

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Explanation:

The AA stands for "angle angle". So we need two pairs of angles to prove the triangles to be similar. The first pair of angles is the vertical angles ONP and MNL, which are congruent. Any pair of vertical angles are always congruent.

The second pair of angles could either be

• angle NOP = angle NML
• angle NPO = angle NLM

so we have a choice on which to pick. The pairing angle NOP = angle NML is not listed in the answer choices, but angle NPO = angle NLM is listed as choice B.

Saying angle NLM = angle LMN is not useful because those two angles are part of the same triangle. The two angles must be in separate triangles to be able to tie the triangles together.

We would use a rigid transformation to have angle NPO move to angle NLM, or vice versa through the use of a rotation and a translation.