What is the law of cosines?

The law of cosines states: c² = a² + b² - 2ab·cos(C). It relates the sides of a triangle to one of its angles and is used to find missing sides or angles.

What is the law of sines?

The law of sines states: a/sin(A) = b/sin(B) = c/sin(C). It relates the sides of a triangle to the sines of their opposite angles.

How does Heron's formula work?

Heron's formula calculates area from three side lengths: A = √[s(s-a)(s-b)(s-c)] where s = (a+b+c)/2 is the semi-perimeter.

What does SSA (ambiguous case) mean?

When you have two sides and an angle opposite one of them, the solution may not be unique. Depending on the values, there can be 0, 1, or 2 valid triangles.

What are the different triangle types?

Equilateral (all sides equal), isosceles (two sides equal), scalene (all sides different), and right (one 90° angle).

Triangle Calculator

Free triangle calculator using law of cosines, law of sines, and Heron's formula. Solve SSS, SAS, ASA, AAS, or SSA triangles and find area, perimeter, and triangle type.

Solve triangles using sides and angles. Calculate missing sides, angles, area, and type.

Law of Cosines: c^{2} = a^{2} + b^{2} - 2 ab cos (C) Area: A = s (s - a) (s - b) (s - c)

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