Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 6.40331242374   b = 12.04215945788   c = 17.26326765016

Area: T = 26.5
Perimeter: p = 35.70773953179
Semiperimeter: s = 17.85436976589

Angle ∠ A = α = 14.77216214922° = 14°46'18″ = 0.25878134309 rad
Angle ∠ B = β = 28.65218284526° = 28°39'7″ = 0.55000687432 rad
Angle ∠ C = γ = 136.5776550055° = 136°34'36″ = 2.38437104795 rad

Height: ha = 8.27772093801
Height: hb = 4.40114104322
Height: hc = 3.07702075657

Median: ma = 14.53444418537
Median: mb = 11.54333963806
Median: mc = 4.30111626335

Inradius: r = 1.4844286365
Circumradius: R = 12.55767774253

Vertex coordinates: A[2; 7] B[5; -10] C[1; -5]
Centroid: CG[2.66766666667; -2.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[2.7176524102; 1.4844286365]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 165.2288378508° = 165°13'42″ = 0.25878134309 rad
∠ B' = β' = 151.3488171547° = 151°20'53″ = 0.55000687432 rad
∠ C' = γ' = 43.42334499448° = 43°25'24″ = 2.38437104795 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     