Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 18.78882942281   b = 7.61657731059   c = 14.03656688476

Area: T = 47.5
Perimeter: p = 40.44397361815
Semiperimeter: s = 20.22198680908

Angle ∠ A = α = 117.2844207294° = 117°17'3″ = 2.04769955779 rad
Angle ∠ B = β = 21.11655068655° = 21°6'56″ = 0.3698535118 rad
Angle ∠ C = γ = 41.66002858409° = 41°36'1″ = 0.72660619577 rad

Height: ha = 5.05663398064
Height: hb = 12.47441111217
Height: hc = 6.76884697489

Median: ma = 6.26549820431
Median: mb = 16.14400123916
Median: mc = 12.5

Vertex coordinates: A[1; -5] B[2; 9] C[-6; -8]
Centroid: CG[-1; -1.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[6.08331257379; 2.34991745736]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 62.71657927064° = 62°42'57″ = 2.04769955779 rad
∠ B' = β' = 158.8844493134° = 158°53'4″ = 0.3698535118 rad
∠ C' = γ' = 138.4399714159° = 138°23'59″ = 0.72660619577 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    