Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
3. Proving Triangles Similar
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Exercise 8 Page 455

Compare the ratios of the given sides.

Are the Triangles Similar? No.
Explanation: See solution.

Practice makes perfect

Let's review the theorems that can help us prove that two triangles are [Concept:Similarity|similar]].

  1. AA (Angle-Angle) ~ Postulate: If two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar.
  2. SSS (Side-Side-Side) ~ Theorem: If the corresponding side lengths of two triangles are proportional, then the triangles are similar.
  3. SAS (Side-Angle-Side) ~ Theorem: If the lengths of two sides of one triangle are proportional to the lengths of two corresponding sides of another triangle and the included angles are congruent, then the triangles are similar.

    We are asked to determine whether the given triangles are similar.

    Notice that ∠ P and ∠ A are congruent. Also, we know the lengths of the sides that include these angles. Let's check whether these sides are proportional. cccc PM/AN & = & 6/6 & = & 1 [0.8em] PR/AD & = & 10/8 & = & 5/4 As we can see, the ratios are not equal. Therefore, the corresponding sides are not proportional and the given triangles are not similar.