Worksheets — Set 20

Geometry · Similarity and right-triangle trigonometry

Print and write your answers. Use diagrams to show thinking.

Warm-up

1. Similar triangles: sides 24, 25, and 26. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 23, find BC/EF = ___ 3. Right triangle: opposite=24, hypotenuse=26. sin θ = ___

_See printable PDF for diagram._

Written practice

1. Similar triangles: sides 23, 24, and 25. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 22, find BC/EF = ___ 3. Right triangle: opposite=23, hypotenuse=25. sin θ = ___ 4. Find missing side using tan 45° = ___ 5. Dilation scale factor 3.5. Image length? ___ 6. Explain why the triangles are similar. 7. Similar triangles: sides 26, 27, and 28. Scale factor? ___ 8. If ΔABC ~ ΔDEF and AB/DE = 25, find BC/EF = ___

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More written practice

1. Right triangle: opposite=26, hypotenuse=28. sin θ = ___ 2. Dilation scale factor 3.8000000000000003. Image length? ___ 3. Similar triangles: sides 29, 30, and 31. Scale factor? ___ 4. If ΔABC ~ ΔDEF and AB/DE = 28, find BC/EF = ___ 5. Right triangle: opposite=29, hypotenuse=31. sin θ = ___ 6. Dilation scale factor 4.1. Image length? ___

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Patterns and rules

1. Similar triangles: sides 40, 41, and 42. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 39, find BC/EF = ___ 3. Right triangle: opposite=40, hypotenuse=42. sin θ = ___

_See printable PDF for diagram._

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Stretch

1. Similar triangles: sides 48, 49, and 50. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 47, find BC/EF = ___

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Parent tip: Set up proportions from similar triangles