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8th Grade Math (Math 8) · Chapter 10 · Lesson 10.5 · Printable PDF

Proportions in Similar Triangles Worksheet with Answer Key

6 problems on proportions in similar triangles: finding unknown sides, ratios of sides, a wrong proportion, all possible side pairs, an A-frame swing set, and a pinhole camera. 2 pages, with a worked answer key.

6 problems2 pagesanswer key
Printable Proportions in similar triangles worksheet with answer key - 8th Grade Math (Math 8) (Page 1 PDF preview)
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What's on the worksheet

  1. Find the missing side of the second triangle in each pair of similar triangles:
    First 3, 5, 6; second's shortest side 12First 8, 10, 14; second's longest side 21First 12, 15, 21; second's middle side 10First 4, 7, 9; second's shortest side 10
  2. Find the sides of similar triangles from the ratios of the sides of the first.
  3. Find the mistake in Ben's proportion for similar triangles.
  4. Find every possible pair of the other side lengths of a similar triangle.
  5. Word problem: lengths in the A-shaped frame of a swing set.
  6. Word problem: the image size in Mia's shoebox pinhole camera.

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Proportions in similar triangles: the lesson ›

More Chapter 10 worksheets: Parallel lines, transversals and the triangle sum