justyourcalculatorTriangle Calculator
Enter any three sides or angles to solve the triangle and see it drawn to scale.
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Triangle Calculator
Solve any triangle from three known values
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How the triangle calculator works
A triangle is fixed by three values as long as at least one of them is a side. Side a is opposite angle A, side b opposite B and side c opposite C, and the angles always add up to 180°.
With three sides (SSS) or two sides and the angle between them (SAS), the law of cosines finds the rest: c² = a² + b² − 2ab·cos C. With one side and two angles (ASA or AAS), the third angle is 180° minus the other two, and the law of sines gives the sides: a/sin A = b/sin B = c/sin C.
Two sides and an angle that isn't between them (SSA) is the ambiguous case: there can be no triangle, one, or two. When two fit, both are shown. Area is ½ab·sin C; the inradius is area divided by the semiperimeter and the circumradius is a / (2 sin A).
Using and checking your result
Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.
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