Triangle Calculator

Enter any two sides (a, b, c) or a side and an angle to solve the triangle. Angles are in degrees.

Enter the values you know — leave the rest blank.

Triangle Formulas

Law of Cosines

c² = a² + b² − 2ab · cos(C)

Law of Sines

a / sin(A) = b / sin(B) = c / sin(C)

Area (Heron’s Formula)

s = (a+b+c)/2    Area = √(s(s−a)(s−b)(s−c))

Angle Sum

A + B + C = 180°

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