Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 6.40331242374   b = 2.23660679775   c = 4.4722135955

Area: T = 3
Perimeter: p = 13.11113281699
Semiperimeter: s = 6.5565664085

Angle ∠ A = α = 143.1330102354° = 143°7'48″ = 2.49880915448 rad
Angle ∠ B = β = 12.0954757077° = 12°5'41″ = 0.21110933332 rad
Angle ∠ C = γ = 24.77551405688° = 24°46'31″ = 0.43224077756 rad

Height: ha = 0.93770425713
Height: hb = 2.6833281573
Height: hc = 1.34216407865

Median: ma = 1.5
Median: mb = 5.40883269132
Median: mc = 4.24326406871

Inradius: r = 0.45876195426
Circumradius: R = 5.33659368645

Vertex coordinates: A[0; 0] B[-2; 4] C[2; -1]
Centroid: CG[0; 1]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[2.13655578655; 0.45876195426]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 36.87698976458° = 36°52'12″ = 2.49880915448 rad
∠ B' = β' = 167.9055242923° = 167°54'19″ = 0.21110933332 rad
∠ C' = γ' = 155.2254859431° = 155°13'29″ = 0.43224077756 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     