Triangle Area Two Sides and Angle Calculator
Calculate triangle area from two sides and the included angle, then recover the third side, perimeter, angles, heights, and circle radii.
Triangle area from two sides and the included angle
This page matches the SAS intent: two sides and the angle between them. If the known angle is opposite one side instead, that is an SSA case and can be ambiguous.
A is area; a and b are the two known sides; C is the included angle.
The calculator uses the law of cosines to recover the third side.
Inputs and outputs
| Input | Rule |
|---|---|
| Two sides | Both side lengths must be greater than zero. |
| Included angle | Enter degrees or radians; the angle must be between 0 and 180 degrees. |
| Outputs | Area, third side, perimeter, angles, heights, inradius, and circumradius. |
Frequently Asked Questions
Sources and References
Calculations are based on the listed reference sources. Links open in a new tab.
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