Math & StatisticsFormula-based · Runs in your browser

Right Triangle Calculator

Solve a right triangle from two known values and calculate all sides, acute angles, altitude, area, and perimeter.

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Inputs

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

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Result

Updates as valid inputs change.

Calculated locally
Leg a
Leg b
Hypotenuse c
Angle α
Angle β
Altitude to hypotenuse
Area
Perimeter

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.

    a²+b²=c²; α=atan(a/b); β=90°−α; area=ab/2; altitude h=ab/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 right triangle from two known values and calculate all sides, acute angles, altitude, area, and perimeter. 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

12
  • ?mode= Known values

    Choice · Required · Default: legs · Accepted values: legs, leg-hypotenuse, hypotenuse-angle, leg-angle, area-leg

  • ?legA= Leg a

    Number · Required · Default: 3 · Used when mode = legs

  • ?legB= Leg b

    Number · Required · Default: 4 · Used when mode = legs

  • ?knownLeg= Known leg a

    Number · Required · Default: 3 · Used when mode = leg-hypotenuse

  • ?knownHypotenuse= Hypotenuse c

    Number · Required · Default: 5 · Used when mode = leg-hypotenuse

  • ?angleHypotenuse= Hypotenuse c

    Number · Required · Default: 5 · Used when mode = hypotenuse-angle

  • ?angleAlpha= Angle α

    Number · Required · Default: 36.869897 · Used when mode = hypotenuse-angle

  • ?angleLeg= Leg a

    Number · Required · Default: 3 · Used when mode = leg-angle

  • ?legAngleAlpha= Angle α

    Number · Required · Default: 36.869897 · Used when mode = leg-angle

  • ?areaInput= Area

    Number · Required · Default: 6 · Used when mode = area-leg

  • ?areaLeg= Leg a

    Number · Required · Default: 3 · Used when mode = area-leg

  • ?angleUnit= Angle input unit

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

Outputs

8
  • sideA Leg a

    Number · Primary output

  • sideB Leg b

    Number

  • hypotenuse Hypotenuse c

    Number

  • angleAlphaResult Angle α

    Number · Suffix: °

  • angleBetaResult Angle β

    Number · Suffix: °

  • altitude Altitude to hypotenuse

    Number

  • area Area

    Number

  • perimeter Perimeter

    Number

Formula notes

a²+b²=c²; α=atan(a/b); β=90°−α; area=ab/2; altitude h=ab/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.