Similar Triangles Calculator

Find a missing side using the scale factor between similar triangles.

Scale factor 1.5

Triangle 2 other side 7.5

Formula: scale = a₂ ÷ a₁ ; b₂ = b₁ × scale

Step-by-step with your numbers:

1. Values used:

2. Triangle 1 side = 4

3. Triangle 2 matching side = 6

4. Triangle 1 other side = 5

6. Scale factor = Triangle 2 matching side / Triangle 1 side = 6 / 4 = 1.5

7. Triangle 2 other side = 7.5

Did we solve your problem today?

Similar triangles have the same shape; corresponding sides are all in the same ratio.

The math behind it

The scale factor is the ratio of any pair of corresponding sides. Multiply a known side of the first triangle by the scale factor to get the matching side of the second.

Worked example

Sides 4 → 6 give scale 1.5, so a side of 5 becomes 7.5.

FAQ

Do angles change?

No — similar triangles have identical angles; only the sizes differ.

The math behind it

Worked example

FAQ

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