Math & StatisticsFormula-based · Runs in your browser

Triangle Calculator

Solve a general triangle from three known values, including at least one side, and calculate sides, angles, area, radii, and medians.

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Inputs

Enter the values you know. Optional fields may be left empty.

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Required

Result

Updates as valid inputs change.

Calculated locally
Side a
Side b
Side c
Angle A
Angle B
Angle C
Area
Perimeter
Inradius
Circumradius
Median to side a
Median to side b
Median to side c
Triangle type
Possible solutions

Saved locally, explained clearly

Drafts, calculations, scenarios, and workflow progress stay in this browser unless you export them.

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Calculation steps

Follow what happened from the selected formula to the displayed answer.

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  1. 1

    Formula selected

    The calculator uses the following formula or method.

    Use the law of cosines for SSS/SAS, the law of sines for ASA/AAS/SSA, and Heron’s formula K=√[s(s−a)(s−b)(s−c)].

  2. 2

    Values entered

    Your values are placed into the calculation.

    Enter values to see what is used in this step.

  3. 3

    Result calculated

    The formula or method produces the following result values.

    Results will appear after a successful calculation.

  4. 4

    Answer formatted

    Displayed values are rounded and formatted using each output’s configured precision.

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Data and privacy

How it works

Solve a general triangle from three known values, including at least one side, and calculate sides, angles, area, radii, and medians. Inputs are calculated locally in the browser, and valid values are retained in the page URL for bookmarking.

Input query strings and outputs

Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.

Input query strings

7
  • ?sideA= Side a

    Number · Optional · Default: 3

  • ?angleA= Angle A

    Number · Optional

  • ?sideB= Side b

    Number · Optional · Default: 4

  • ?angleB= Angle B

    Number · Optional

  • ?sideC= Side c

    Number · Optional · Default: 5

  • ?angleC= Angle C

    Number · Optional

  • ?angleUnit= Angle unit

    Choice · Required · Default: degrees · Accepted values: degrees, radians

Outputs

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  • sideAResult Side a

    Number · Primary output

  • sideBResult Side b

    Number

  • sideCResult Side c

    Number

  • angleAResult Angle A

    Number · Suffix: °

  • angleBResult Angle B

    Number · Suffix: °

  • angleCResult Angle C

    Number · Suffix: °

  • area Area

    Number

  • perimeter Perimeter

    Number

  • inradius Inradius

    Number

  • circumradius Circumradius

    Number

  • medianA Median to side a

    Number

  • medianB Median to side b

    Number

  • medianC Median to side c

    Number

  • triangleType Triangle type

    Text

  • solutionCount Possible solutions

    Whole number

Formula notes

Use the law of cosines for SSS/SAS, the law of sines for ASA/AAS/SSA, and Heron’s formula K=√[s(s−a)(s−b)(s−c)].

Input guidance

Use consistent units for every length or measurement in the same calculation. Results are educational mathematical estimates and should be checked before high-stakes use.

Sources
Limitations
  • Results depend on the selected method and input assumptions. Displayed decimals may be rounded; retain appropriate precision for later calculations.