Proving Triangle Similarity

10th GradeMath45 min

Learning Objective

I can prove that two triangles are similar using the AA, SAS, and SSS similarity theorems.

Lesson Flow

Watch Video

7 min

Triangle Similarity - SSS, SAS, and AA 128-2.28

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Guided Notes

9 min

Key concepts students will learn:

  • Side-Side-Side (SSS) similarity states that two triangles are similar if the lengths of their corresponding sides are proportional.

  • Side-Angle-Side (SAS) similarity states that two triangles are similar if they have two pairs of corresponding sides that are proportional and the included angles are congruent.

  • Angle-Angle (AA) similarity states that two triangles are similar if they have two pairs of corresponding angles that are congruent.

Practice

14 min

9 questions • Multiple choice & Short answer

Exit Ticket

5 min

Triangle PQR has sides PQ = 6, QR = 8, and RP = 10. Triangle XYZ has sides XY = 18, YZ = 24, and ZX = 30. Are these triangles similar? Show the ratios of corresponding sides to justify your answer.

Teacher Guide

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  • Answer keys for all questions
  • Differentiation strategies
  • Extension activities
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