Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 4.12331056256   b = 18.02877563773   c = 14.21326704036

Area: T = 12.5
Perimeter: p = 36.36435324065
Semiperimeter: s = 18.18217662032

Angle ∠ A = α = 5.59993393365° = 5°35'58″ = 0.09877269074 rad
Angle ∠ B = β = 154.7476836605° = 154°44'49″ = 2.70108418058 rad
Angle ∠ C = γ = 19.65438240581° = 19°39'14″ = 0.34330239404 rad

Height: ha = 6.06333906259
Height: hb = 1.38767504906
Height: hc = 1.75989938618

Median: ma = 16.10112421881
Median: mb = 5.31550729064
Median: mc = 10.97772492001

Inradius: r = 0.68875019654
Circumradius: R = 21.12986535302

Vertex coordinates: A[8; 0] B[-3; 9] C[-7; 10]
Centroid: CG[-0.66766666667; 6.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-1.45875041667; 0.68875019654]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 174.4010660663° = 174°24'2″ = 0.09877269074 rad
∠ B' = β' = 25.25331633946° = 25°15'11″ = 2.70108418058 rad
∠ C' = γ' = 160.3466175942° = 160°20'46″ = 0.34330239404 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     