Triangle Trigonometry Solver
Solve any triangle given three known values (SSS, SAS, ASA, AAS) using trig laws.
Inputs
Area
15.1554
Side a
5.0000
Side b
7.0000
Side c
6.2450
Angle A
43.8979°
Angle B
76.1021°
Angle C
60.0000°
Perimeter
18.2450
Step by step
Sides
= a=5, b=7, c=6.245
Angles
= A=43.8979°, B=76.1021°, C=60°
Area
½·a·b·sin C = ½·5·7·sin(60°)
= 15.155445
How it works
This solver handles any triangle (right or oblique) using the Law of Cosines for SSS/SAS and the Law of Sines for ASA/AAS. It reports all sides, angles, area and perimeter.
Formulas
Law of Cosines
c² = a² + b² − 2ab·cos C
- a
- Side a
- b
- Side b
- c
- Side c
- C
- Angle opposite c
Law of Sines
a/sin A = b/sin B = c/sin C
- a
- Side a
- A
- Angle opposite a
Area
Area = ½ · a · b · sin C
- a
- Side a
- b
- Side b
- C
- Included angle
Frequently Asked Questions
Which configuration should I choose?
SSS if you know all three sides, SAS if you know two sides and the angle between them, ASA if you know two angles and the side between them, AAS if you know two angles and a non-included side.
Can this solve a right triangle?
Yes — a right triangle is a special case. Enter 90° as one angle in ASA/AAS mode, or enter two legs and 90° in SAS mode.