Trigonometry
Law of Cosines Calculator
Lets users solve and check law of cosines instantly with formula, steps and examples — no manual math.
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°
0180
Your result
Third side (c)
6.245
c = √(a² + b² − 2ab·cosC) = 6.2450.
About this calculator
Law of cosines: c² = a² + b² − 2ab·cos(C). Finds the third side of a triangle from two sides and their included angle; reduces to Pythagoras when C = 90°.
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