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Similar Triangles Worksheet

Each problem shows a small triangle and a larger similar copy. Find the scale factor, then the missing side.

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Example worksheets

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Best for: Grades 7–9

Scale factor

Divide a side of the big triangle by the matching side of the small one. Multiply the small triangle’s other sides by that factor to find the missing length.

Make it a timed challenge

Put a visual classroom timer on the board and see how many problems students can finish before the time runs out. Print a new version tomorrow and try to beat the score.

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Frequently asked questions

Are scale factors whole numbers?

Some are, and some are 1.5 or 2.5.

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