Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 13.03884048104   b = 19.10549731745   c = 6.70882039325

Area: T = 22.5
Perimeter: p = 38.85215819174
Semiperimeter: s = 19.42657909587

Angle ∠ A = α = 20.55660452196° = 20°33'22″ = 0.35987706703 rad
Angle ∠ B = β = 149.0366243468° = 149°2'10″ = 2.60111731533 rad
Angle ∠ C = γ = 10.40877113125° = 10°24'28″ = 0.182164883 rad

Height: ha = 3.45113424498
Height: hb = 2.35554076517
Height: hc = 6.70882039325

Median: ma = 12.7487548784
Median: mb = 4.03111288741
Median: mc = 16.00878105936

Inradius: r = 1.15882539958
Circumradius: R = 18.56766965888

Vertex coordinates: A[-9; -5] B[-6; 1] C[5; 8]
Centroid: CG[-3.33333333333; 1.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-1.93304233264; 1.15882539958]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 159.444395478° = 159°26'38″ = 0.35987706703 rad
∠ B' = β' = 30.96437565321° = 30°57'50″ = 2.60111731533 rad
∠ C' = γ' = 169.5922288688° = 169°35'32″ = 0.182164883 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     