Find corresponding side lengths in similar triangles with this free similar triangle side lengths worksheet. The practice page contains eight numbered questions, with a separate answer page so learners can attempt the work before checking. It is designed for focused practice after the underlying idea has been introduced, rather than as a timed test or a placement assessment.
How to work through the questions
Form a scale factor from one pair of corresponding sides, then apply it to the second pair. Begin by identifying the information supplied and the quantity you need to find. Write at least one intermediate step beside each question; the working is often more useful than a final answer when you are deciding what to review.
A first-question check
The first prompt is: Similar triangles: side 2 corresponds to 6. A second side 3 corresponds to what length? The checked result is 9. Use the method above to explain how the given information leads to that result. Then cover the key and solve the remaining questions independently.
What to watch for
Match corresponding sides before taking a ratio. These prompts explicitly identify the pairs. If an answer differs from the key, compare one step at a time. Mark whether the issue came from reading the prompt, choosing an operation, calculating, or writing the units. Correct that step and retry the question without copying the answer.
Questions in text
- Similar triangles: side 2 corresponds to 6. A second side 3 corresponds to what length?
- Similar triangles: side 3 corresponds to 9. A second side 4 corresponds to what length?
- Similar triangles: side 4 corresponds to 12. A second side 5 corresponds to what length?
- Similar triangles: side 5 corresponds to 15. A second side 6 corresponds to what length?
- Similar triangles: side 6 corresponds to 18. A second side 7 corresponds to what length?
- Similar triangles: side 7 corresponds to 21. A second side 8 corresponds to what length?
- Similar triangles: side 8 corresponds to 24. A second side 9 corresponds to what length?
- Similar triangles: side 9 corresponds to 27. A second side 10 corresponds to what length?
Answer key
- 9
- 12
- 15
- 18
- 21
- 24
- 27
- 30
Download and print
Use Download image beneath either page to save its original 2550 × 3300 PNG. For a PDF, choose US Letter or A4 in that page’s controls and select Download PDF; the theme creates the file in your browser. Match the printer paper size, keep uniform scaling and check the margins in print preview. Print a test copy before making a classroom set. Keep the answer sheet separate during independent practice. These original worksheets are for personal and classroom use; share this article link when recommending them.