Math

Law of Cosines Calculator

Third side from two sides and the included angle (SAS).

Side c

This free Law of Cosines Calculator covers Third side from two sides and the included angle (SAS).

c² = a² + b² − 2ab cos C. Other math tools are linked below.

Law of Cosines Calculator — how it works

Third side from two sides and the included angle (SAS). Typical inputs are Side a, Side b and Included angle C (°). How it works beside the form states the identity the Law of Cosines Calculator applies.

FAQ

How do I use the Law of Cosines Calculator?

Open the Law of Cosines Calculator, fill Side a, Side b and Included angle C (°), and read the result. c² = a² + b² − 2ab cos C.

What formula does the Law of Cosines Calculator use?

The Law of Cosines Calculator uses the identity in How it works. In words: c² = a² + b² − 2ab cos C.

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