Worksheets — Set 10

Geometry · Similarity and right-triangle trigonometry

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

Warm-up

1. Similar triangles: sides 14, 15, and 16. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 13, find BC/EF = ___ 3. Right triangle: opposite=14, hypotenuse=16. sin θ = ___

_See printable PDF for diagram._

Written practice

1. Similar triangles: sides 13, 14, and 15. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 12, find BC/EF = ___ 3. Right triangle: opposite=13, hypotenuse=15. sin θ = ___ 4. Find missing side using tan 45° = ___ 5. Dilation scale factor 2.5. Image length? ___ 6. Explain why the triangles are similar. 7. Similar triangles: sides 16, 17, and 18. Scale factor? ___ 8. If ΔABC ~ ΔDEF and AB/DE = 15, find BC/EF = ___

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More written practice

1. Right triangle: opposite=16, hypotenuse=18. sin θ = ___ 2. Dilation scale factor 2.8. Image length? ___ 3. Similar triangles: sides 19, 20, and 21. Scale factor? ___ 4. If ΔABC ~ ΔDEF and AB/DE = 18, find BC/EF = ___ 5. Right triangle: opposite=19, hypotenuse=21. sin θ = ___ 6. Dilation scale factor 3.1. Image length? ___

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Patterns and rules

1. Similar triangles: sides 30, 31, and 32. Scale factor? ___ 2. If ΔABC ~ ΔDEF and AB/DE = 29, find BC/EF = ___ 3. Right triangle: opposite=30, hypotenuse=32. sin θ = ___

_See printable PDF for diagram._

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Parent tip: Set up proportions from similar triangles