Triangle Angles from Sides
Find all three angles opposite the supplied side lengths.
Your numbers
Angle A
Use consistent units. The result follows the assumptions you enter.
Scenario comparison
Up to three snapshots in this tab. Loading one replaces the current inputs.
Formula
A=acos((b²+c²−a²)/(2bc)); similarly for B and C.
Find all three angles opposite the supplied side lengths.
Worked example
- Side a
- 3
- Side b
- 4
- Side c
- 5
- Angle A
- 36.8698976458 °
- Angle B
- 53.1301023542 °
- Angle C
- 90 °
Scope and limitations
Use consistent units. The result follows the assumptions you enter.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: e3d29fba1e05 · Example checked: