Cosine Law Calculator and Solver
Online calculator, based on the cosine Law , to solve triangle problems. The first calculator solves triangle problems when 3 sides are given (SSS case) and the second calculator solves triangle problems when 2 sides and their included angle are given (SAS case).
The cosine laws are given by:
1)
a 2 = b 2 + c 2 - 2 b c cos(A)
which gives A = arccos [ (b 2 + c 2 - a 2) / 2 b c ]
2) b 2 = a 2 + c 2 - 2 a c cos(B)
which gives B = arccos [ (a 2 + c 2 - b 2) / 2 a c ]
3) c 2 = b 2 + a 2 - 2 b a cos(C)
which gives C = arccos [ (b 2 + a 2 - c 2) / 2 a b ]
1 - Use Cosine Law Calculator when 3 Sides are Given (SSS case)
Enter the 3 sides a, b and c as positive real numbers and press "enter". The outputs are the 3 angles A (opposite side a), B (opposite side b) and C (opposite side c) in DEGREES.
Note
For a triangle to exist, the sum of any two sides must be greater than the third side.
1 - Use Cosine Law Calculator when 2 Sides and the Included Angle are Given (SAS case)
Enter the given angle in A (in DEGREES) and the two sides in b and c as positive real numbers and press "enter". The outputs are side a and 2 angles B (opposite side b) and C (opposite side c) in DEGREES.
More References and Links
Online Geometry Calculators and Solvers.
Sine Law Calculator and Solver.
Cosine Law Problems.
Sine Law Problems.
Laws of Sines and Cosines Problems Calculator.