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THE FEUTEX TOOLKIT

Parabola Focus and Directrix

Locate the focus and directrix of a vertical parabola and calculate its focal chord width.

Geometry workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaFocus X = h; Focus Y = k+1/(4*a); Directrix Y = k-1/(4*a); Latus Rectum = abs(1/a)
Sources and model references

How to use this tool

  1. Enter the labeled inputs using consistent units.
  2. Check the stated assumptions and calculate.
  3. Review each output and compare another input scenario.

Try this example

{
  "a": 0.25,
  "h": 2,
  "k": 3
}

Accuracy and scope

Vertical parabola y = a(x−h)² + k. Finite floating-point arithmetic; results can lose precision near singular or extreme inputs.

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.