Similar Triangles Scale Factor Calculator

Find the scale factor and missing side for similar triangles using proportional sides.

GeometryTrianglesHigh School Math

Calculator

Known side in triangle A

Corresponding side in triangle B

Another side in triangle A

Please enter valid values.

What this calculator teaches

Similar triangles have equal angles and proportional side lengths.

Once the scale factor is known, every side of one triangle can be scaled to the corresponding side of the other.

Formula & Symbols

Concept	Formula	Meaning
Scale factor	`k=B/A`	Ratio of corresponding sides.
Missing side	`x_B=kx_A`	Multiply by the scale factor.

Step-by-Step Examples

Example 1

A side 6 corresponds to B side 9; another A side is 10

Scale factor is 9/6 = 1.5.
Multiply 10 by 1.5.

✓ The corresponding side in triangle B is 15.

Where students use this

🎓

High school and college

Use the calculator to check homework and understand each step.

📊

Modeling and data

Connect formulas to tables, graphs, and real values.

🧪

Science and engineering

Use the result inside physics, chemistry, engineering, and lab problems.

💻

Computer science

Apply the same math to algorithms, simulations, and numerical work.

Common Mistakes to Avoid

⚠️

Mixing notation with calculator input

Mathematical notation is compact, but calculators need explicit numbers and operators.

⚠️

Skipping domain restrictions

Some formulas only work when denominators are nonzero, logs have positive inputs, and square roots are valid.

⚠️

Rounding too early

Keep extra decimals while solving and round only the final answer.

Frequently Asked Questions

Is this calculator for learning or only answers? ▾

It is designed for both. The result panel gives the answer, while the examples and explanation show why the method works.

Can I use decimals and negatives? ▾

Yes, unless the specific topic has a restriction such as a positive base, positive radicand, or nonzero denominator.

Why might my answer differ from a textbook? ▾

Different rounding, equivalent algebraic forms, or a different interpretation of the input can produce a different-looking but equivalent result.

Does this replace solving by hand? ▾

No. It helps verify work and understand the steps, but students should still practice the method manually.

Related Math Calculators

Formula Explorer connections

Interpretation: This relationship connects dimensions, coordinates, angles or trigonometric ratios to a geometric measurement. Assumption: Use a consistent angle mode and length unit, identify the intended shape or coordinate system, and verify that the supplied dimensions form valid geometry.

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