Instantly calculate the angles of any triangle with our free Triangle Angle Calculator. Whether you provide two angles or all three side lengths, this tool helps you understand triangle geometry and apply the fundamental sum of angles formula for quick solutions. Discover how to find a missing angle in right, acute, or obtuse triangles effortlessly.
Formula:
The sum of the angles in any Euclidean triangle is always 180 degrees. So, if you know two angles, finding the third is straightforward:
- If Angle A and Angle B are known: C = 180° - (A + B)
If you know all three side lengths (a, b, c) but no angles, you can use the Law of Cosines to find each angle:
- For Angle A: A = arccos((b² + c² - a²) / (2bc))
- For Angle B: B = arccos((a² + c² - b²) / (2ac))
- For Angle C: C = arccos((a² + b² - c²) / (2ab))
Where:
- A, B, C = Interior angles of the triangle (in degrees)
- a, b, c = Lengths of the sides opposite to angles A, B, C respectively