Law of Cosines
Calculate Law of Cosines instantly with the exact formula and a worked example.
Law of Cosines
a
b
Angle C°
Side c
5.5678
More about: Law of Cosines
What it calculates
The “Law of Cosines” calculator computes Side c from 3 parameters: a, b, angle c (°).
A core calculation for studying, engineering tasks, and checking solutions.
Example calculation
With parameters a = 5, b = 6, Angle C = 60 ° the result is 5.57.
How to use
- Enter a, b and angle c — each field above is adjustable with a slider.
- Side c is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is Law of Cosines calculated?
The Law of Cosines calculator computes Side c from a, b, angle c. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the Law of Cosines calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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