Triangle calculator VC

Please enter the coordinates of the three vertices

Right scalene triangle.

Sides: a = 15.23215462117   b = 7.61657731059   c = 17.02993863659

Area: T = 58
Perimeter: p = 39.87767056835
Semiperimeter: s = 19.93883528418

Angle ∠ A = α = 63.43549488229° = 63°26'6″ = 1.10771487178 rad
Angle ∠ B = β = 26.56550511771° = 26°33'54″ = 0.4643647609 rad
Angle ∠ C = γ = 90° = 1.57107963268 rad

Height: ha = 7.61657731059
Height: hb = 15.23215462117
Height: hc = 6.81217545464

Median: ma = 10.77703296143
Median: mb = 15.77003184681
Median: mc = 8.5154693183

Inradius: r = 2.90989664758
Circumradius: R = 8.5154693183

Vertex coordinates: A[8; -9; 0] B[-5; 2; 0] C[1; -12; 0]
Centroid: CG[1.33333333333; -6.33333333333; 0]
Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 116.5655051177° = 116°33'54″ = 1.10771487178 rad
∠ B' = β' = 153.4354948823° = 153°26'6″ = 0.4643647609 rad
∠ C' = γ' = 90° = 1.57107963268 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     