How to use the similar triangles scale calculator
Find an unknown side using similar triangles. Enter known side 1, matching side 1, known side 2 in the fields above; the scale factor, matching side 2 are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “proportional sides”, “shadow height”, “scale factor”, “calculate similar triangles scale”, “find scale factor”.
Formula
Variables
- a — Known side 1
- b — Matching side 1
- c — Known side 2
Worked example
With known side 1 = 6, matching side 1 = 15, known side 2 = 8, the calculator gives scale factor ≈ 2.5; matching side 2 ≈ 20.
Frequently asked questions
What is the similar triangles scale calculator used for?
Find an unknown side using similar triangles. It helps with questions such as “proportional sides”, “shadow height”, “scale factor”.
What is the formula for the similar triangles scale calculation?
Scale factor = b / a. Matching side 2 = c × [Scale factor]. Here a is known side 1, b is matching side 1, c is known side 2.
What inputs do I need for the similar triangles scale calculator?
You need known side 1, matching side 1, known side 2. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the similar triangles scale calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the similar triangles scale result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.