Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 5.83109518948   b = 9.48768329805   c = 7.21111025509

Area: T = 21
Perimeter: p = 22.52988874263
Semiperimeter: s = 11.26444437131

Angle ∠ A = α = 37.87549836511° = 37°52'30″ = 0.66110431689 rad
Angle ∠ B = β = 92.72663109939° = 92°43'35″ = 1.61883794301 rad
Angle ∠ C = γ = 49.3998705355° = 49°23'55″ = 0.86221700547 rad

Height: ha = 7.2032940576
Height: hb = 4.42771887242
Height: hc = 5.82443520604

Median: ma = 7.90656941504
Median: mb = 4.52876925691
Median: mc = 7

Inradius: r = 1.86442731532
Circumradius: R = 4.74987914682

Vertex coordinates: A[-3; 6] B[-7; 12] C[-12; 9]
Centroid: CG[-7.33333333333; 9]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-0.08987749121; 1.86442731532]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.1255016349° = 142°7'30″ = 0.66110431689 rad
∠ B' = β' = 87.27436890061° = 87°16'25″ = 1.61883794301 rad
∠ C' = γ' = 130.6011294645° = 130°36'5″ = 0.86221700547 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     