➗ Law of Cosines Side Calculator
Find the third side from two sides and included angle.
Result
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How this calculator works
Find the third side from two sides and included angle.
Formula
c=√(a²+b²-2ab cos C)
Example
a=5, b=7, C=60° gives c≈6.25.
Frequently asked questions
What does the Law of Cosines Side Calculator do?
Find the third side from two sides and included angle.
Are the results exact?
The calculator follows the displayed formula. Rounded display values may differ slightly from full-precision results.
Can I use negative or decimal values?
Most fields accept decimals and negative values when they make sense for the formula.
How should I check an important result?
Review the formula, verify your entries, and confirm high-stakes work with a qualified teacher or professional.