Law of Cosines Triangle Calculator

Your details

SSS: provide all three sides. SAS: provide sides a and b and their included angle C.
Length of side a (opposite angle A).
m
Length of side b (opposite angle B).
m
Length of side c (opposite angle C). Leave as-is for SAS mode (will be computed).
AreaAcute triangle
17.3205m²

Triangle's surface area (Heron's formula).

Angle A60
Angle B81.7868
Angle C38.2132
Perimeter20m
Semi-perimeter10m
Inradius1.7321m
Circumradius4.0415m
Triangle typescalene, acute

Triangle solved: scalene, acute.

  • The three angles are 60.0000 deg, 81.7868 deg, and 38.2132 deg - they sum to 180.0000 as expected.
  • Area is 17.3205 m², perimeter is 20.0000 m.
  • The inscribed circle has radius 1.7321 m; the circumscribed circle has radius 4.0415 m.

Next stepTo cross-check, you can use the Law of Sines: a / sin(A) = b / sin(B) = c / sin(C). All three ratios should be equal.

 = Powered by OnlyCalculators