Proving Triangle Similarity

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Objective

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

Part 1 of 4

Warm-up video

HCCMathHelp · 6:58

We don't generate video — this one is by HCCMathHelp on YouTube. The practice questions and exit ticket below were drafted by AI for this objective, and every question is editable in the teacher guide.

Part 2 of 4

Key concepts

3 concepts

  1. 1

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

  2. 2

    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.

  3. 3

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

Part 3 of 4

Practice

9 questions

1

State the Side-Side-Side (SSS) Similarity Theorem in your own words.

2

If triangle PQR has sides PQ = 5, QR = 7, RP = 9 and triangle XYZ has sides XY = 10, YZ = 14, and ZX = 18, are the triangles similar? Explain why or why not.

Part 4 of 4

Exit ticket

Quick comprehension check

“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.”

Sample answer included in the free materials

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