Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 9.11104335791   b = 4.89989794856   c = 5.19661524227

Area: T = 9.89994949366
Perimeter: p = 19.20655654874
Semiperimeter: s = 9.60327827437

Angle ∠ A = α = 128.9422441269° = 128°56'33″ = 2.25504701457 rad
Angle ∠ B = β = 24.72333108842° = 24°43'24″ = 0.43215031769 rad
Angle ∠ C = γ = 26.33442478469° = 26°20'3″ = 0.4659619331 rad

Height: ha = 2.1733221472
Height: hb = 4.04114518843
Height: hc = 3.81103173777

Median: ma = 2.17994494718
Median: mb = 7
Median: mc = 6.83773971656

Inradius: r = 1.03108985636
Circumradius: R = 5.85767073009

Vertex coordinates: A[3; 0; 3] B[-2; 1; 4] C[7; 2; 5]
Centroid: CG[2.66766666667; 1; 4]
Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 51.0587558731° = 51°3'27″ = 2.25504701457 rad
∠ B' = β' = 155.2776689116° = 155°16'36″ = 0.43215031769 rad
∠ C' = γ' = 153.6665752153° = 153°39'57″ = 0.4659619331 rad

How did we calculate this triangle?

1. We compute side a from coordinates using the Pythagorean theorem 2. We compute side b from coordinates using the Pythagorean theorem 3. We compute side c from coordinates using the Pythagorean theorem Now we know the lengths of all three sides of the triangle and the triangle is uniquely determined. Next we calculate another its characteristics - same procedure as calculation of the triangle from the known three sides SSS. 4. The triangle circumference is the sum of the lengths of its three sides 5. Semiperimeter of the triangle 6. The triangle area using Heron's formula 7. Calculate the heights of the triangle from its area. 8. Calculation of the inner angles of the triangle using a Law of Cosines     