Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 8.48552813742   b = 21.09550231097   c = 27.29546881279

Area: T = 69
Perimeter: p = 56.87549926119
Semiperimeter: s = 28.43774963059

Angle ∠ A = α = 13.86773010525° = 13°52'2″ = 0.24220300617 rad
Angle ∠ B = β = 36.57330309785° = 36°34'23″ = 0.6388319808 rad
Angle ∠ C = γ = 129.5659667969° = 129°33'35″ = 2.26112427838 rad

Height: ha = 16.26334559673
Height: hb = 6.54218273913
Height: hc = 5.05659288076

Median: ma = 24.02108242989
Median: mb = 17.24109396496
Median: mc = 8.5

Inradius: r = 2.42663739416
Circumradius: R = 17.70217135223

Vertex coordinates: A[-19; -8] B[8; -12] C[2; -6]
Centroid: CG[-3; -8.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[3.27703300951; 2.42663739416]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 166.1332698948° = 166°7'58″ = 0.24220300617 rad
∠ B' = β' = 143.4276969021° = 143°25'37″ = 0.6388319808 rad
∠ C' = γ' = 50.4440332031° = 50°26'25″ = 2.26112427838 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     