Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 7.61657731059   b = 12.04215945788   c = 6.40331242374

Area: T = 21.5
Perimeter: p = 26.06604919221
Semiperimeter: s = 13.0330245961

Angle ∠ A = α = 33.89661665634° = 33°53'46″ = 0.59215997103 rad
Angle ∠ B = β = 118.1421601232° = 118°8'30″ = 2.06219599251 rad
Angle ∠ C = γ = 27.96222322044° = 27°57'44″ = 0.48880330182 rad

Height: ha = 5.6466176613
Height: hb = 3.57109556337
Height: hc = 6.71554717612

Median: ma = 8.86600225733
Median: mb = 3.64400549446
Median: mc = 9.55224865873

Inradius: r = 1.65500072266
Circumradius: R = 6.82879679675

Vertex coordinates: A[1; -6] B[5; -1] C[2; 6]
Centroid: CG[2.66766666667; -0.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-0.88325620049; 1.65500072266]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.1043833437° = 146°6'14″ = 0.59215997103 rad
∠ B' = β' = 61.85883987677° = 61°51'30″ = 2.06219599251 rad
∠ C' = γ' = 152.0387767796° = 152°2'16″ = 0.48880330182 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     