Use this triangle angles calculator to calculate triangle angles from its sides. Learn the triangle angle sum formula and apply it easily.
A, B, C = angles in degrees
a, b, c = sides of triangle
| a | b | c | Angle A | Angle B | Angle C |
|---|---|---|---|---|---|
| 3 | 4 | 5 | 36.869898 | 53.130102 | 90.000000 |
| 5 | 5 | 6 | 53.130102 | 53.130102 | 73.739796 |
| 6 | 8 | 10 | 36.869898 | 53.130102 | 90.000000 |
| 7 | 7 | 7 | 60.000000 | 60.000000 | 60.000000 |
| 8 | 15 | 17 | 28.072486 | 61.927514 | 90.000000 |
To manually calculate triangle angles:
1. Use Law of Cosines: A = arccos((b² + c² − a²) / (2bc))
2. Compute B similarly: B = arccos((a² + c² − b²) / (2ac))
3. Compute C = 180° − A − B
This triangle angles calculator computes all three angles with six-decimal precision using the Law of Cosines.
• The sum of angles in any triangle is 180°.
• Right triangles always have a 90° angle.
• Equilateral triangles have three 60° angles.
• Angle calculations are crucial in trigonometry and navigation.
• Angle bisectors intersect at the incenter of the triangle.