Find the side opposite angle C from sides a and b and the included angle C (SAS).
| Side c | – |
Use this calculator when you know two sides and the included angle (SAS). The law of cosines is c² = a² + b² − 2ab cos C, so c = √(a² + b² − 2ab cos C). At C = 90° this is Pythagoras. At C = 0° you get |a − b|; at C = 180° you get a + b.
Sides a and b must be positive. Angle C is in degrees. This page returns only side c, not the other angles (use the law of sines afterward if you need them).
Side a: One side adjacent to angle C.
Side b: The other side adjacent to C.
Angle C (°): The included angle between a and b.
Side c: Side opposite C.
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