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Lesson

Similarity vs Congruence

While similar figures have the same shape, congruent figures have the same shape and size. In similar figures, sides are proportional, but in congruent figures, they are equal in length. All congruent figures are similar, but not all similar figures are congruent. For example, two squares of different sizes are similar but not congruent.

35min lesson

Objectives3 goals Lesson9 blocks Review9 assets Practice32 items

Learning objectives

What to understand

3 goals

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Understand similarity vs congruence in the Similarity chapter.
Connect the idea with formulas, examples, and exam-style questions.
Use flashcards, notes, MCQs, and LAQs to check readiness.

Lesson

Step-by-step lesson

9 sections

Example

Prove triangles similar using AA criterion

In triangle ABC, angle A = 50° and angle B = 70°. In triangle DEF, angle D = 50° and angle E = 70°. Prove that triangle ABC is similar to triangle DEF. 1. ∠A = ∠D and ∠B = ∠E. 2. Therefore, two corresponding angles of the two triangles are equal. 3. Hence, ΔABC ~ ΔDEF by AA similarity. Final answer: ΔABC ~ ΔDEF Exam tip: Identify matching pairs of angles in both triangles. Common mistake: Confusing angle measures or misapplying the AA criterion.

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9 lesson sections8 cards / 1 notes18 MCQs / 14 written questions

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Similarity vs Congruence

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32 prompts

18 MCQs14 LAQsMixed test

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Similarity

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Similarity vs Congruence

What to understand

Step-by-step lesson

Prove triangles similar using AA criterion

Prove two triangles are similar using AA criterion.

Proving Similar Triangles Using AA Criterion