Find a missing corresponding side using a triangle scale factor
Result
Missing Corresponding Side
Step-by-Step Derivation
Similar Triangles Formula
x = target side × (matching side / known side)
Similar triangles have equal angles and proportional side lengths. Once one corresponding side pair gives the scale factor, that same factor can be applied to another side to find its match.
⚠Make sure the two known sides are corresponding sides. If the side pairing is wrong, the calculated missing side will also be wrong.
How Similar Triangles Work
Similar triangles keep the same shape while changing size. Every side in the larger or smaller triangle is multiplied by the same scale factor.
Scale Factor
The ratio between matching sides.
Corresponding Sides
Sides must be paired by position.
Proportion Setup
Equal side ratios create the equation.
Common Mistake
Mixing nonmatching sides gives a bad result.
💡 Example: If 4 corresponds to 10, the scale factor is 2.5. A side of 6 corresponds to 15.
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