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Chord Sagitta Residual Tool

Compare supplied minor-segment sagitta to a circular chord using a cancellation-resistant expression.

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Description

Compute the minor sagitta using its rationalized expression and return measuredSagitta minus expectedSagitta.

Circle calculations distinguish radius, diameter, chord, sagitta, tangent, and oriented offsets. Branch choices determine signs and which arc or segment is meant; a scalar identity does not always establish an actual geometric construction.

Compute the minor sagitta using its rationalized expression and return measuredSagitta minus expectedSagitta.

When to use this tool

Use Chord Sagitta Residual when you need a local circle identity with explicit radius and branch conventions.

How to use the tool and how it works

  1. Enter radius, chordLength, measuredSagitta. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read expectedSagitta, residual. Use the output convention below.

Require positive radius and chordLength within [0, 2r]. Compute the minor sagitta using its rationalized expression and return measuredSagitta minus expectedSagitta.1

Input fieldMeaning and unitsAccepted input
radiusRadius in the common length unit, with its geometric role defined above.Required. Finite number; strictly above 0.
chordLengthChord LengthRequired. Finite number; minimum 0.
measuredSagittaMeasured SagittaRequired. Finite number.
Output fieldInterpretationReturned shape
expectedSagittaExpected SagittaRequired. Finite number.
residualResidualRequired. Finite number.
json
{
  "input": {
    "radius": 5,
    "chordLength": 8,
    "measuredSagitta": 3
  },
  "output": {
    "expectedSagitta": 2,
    "residual": 1
  }
}

Limitations and assumptions

  • Lengths share units; the result uses the minor segment branch and does not establish a full circle, measurement precision, or tolerance acceptance.
  • Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
  • Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Construct the circles, chord, or segment in coordinates when existence or orientation matters. Use the complete geometry and an appropriate tolerance for intersection or tangency decisions.

References

  1. Calculation and input contract: geometry/chord-sagitta-residual — tool.io

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