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THE FEUTEX TOOLKIT

Common External Tangent of Two Circles

Find the straight external tangent length between circles for a geometric construction.

Geometry workspace● Runs in your browser
01 Your input
02 Your result
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FormulaTangent Length = sqrt(d**2-(r-s)**2); Radius Offset Angle = asin((r-s)/d)*180/PI
Sources and model references

Made for real tasks

  • Find the straight external tangent length between circles for a geometric construction.
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Worked example

Inputs

First radius
3 length
Second radius
1 length
Center separation
10 length

Expected results

Tangent Length
9.797958971 length
Radius Offset Angle
11.53695903 degrees

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter first radius, second radius, center separation.
  2. Use the displayed units and confirm the model assumptions.
  3. Calculate and compare the outputs against your input scenario.

Try this example

{
  "r": 3,
  "s": 1,
  "d": 10
}

Accuracy and scope

External common tangent only; this is not the full belt length.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.