Triangle calculator SSS - result

Please enter the triangle sides:

Acute scalene triangle.

Sides: a = 12   b = 17   c = 20

Area: T = 101.6665812838
Perimeter: p = 49
Semiperimeter: s = 24.5

Angle ∠ A = α = 36.7299236457° = 36°43'45″ = 0.64110461079 rad
Angle ∠ B = β = 57.91100487437° = 57°54'36″ = 1.01107210206 rad
Angle ∠ C = γ = 85.36107147993° = 85°21'39″ = 1.49898255251 rad

Height: ha = 16.94443021397
Height: hb = 11.96106838633
Height: hc = 10.16765812838

Median: ma = 17.56441680703
Median: mb = 14.13332940251
Median: mc = 10.79435165725

Inradius: r = 4.15496250138
Circumradius: R = 10.03328711445

Vertex coordinates: A[20; 0] B[0; 0] C[6.375; 10.16765812838]
Centroid: CG[8.79216666667; 3.38988604279]
Coordinates of the circumscribed circle: U[10; 0.81114822249]
Coordinates of the inscribed circle: I[7.5; 4.15496250138]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.2710763543° = 143°16'15″ = 0.64110461079 rad
∠ B' = β' = 122.0989951256° = 122°5'24″ = 1.01107210206 rad
∠ C' = γ' = 94.63992852007° = 94°38'21″ = 1.49898255251 rad

How did we calculate this triangle?

1. The triangle circumference is the sum of the lengths of its three sides 2. Semiperimeter of the triangle 3. The triangle area using Heron's formula 4. Calculate the heights of the triangle from its area. 5. Calculation of the inner angles of the triangle using a Law of Cosines     