Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 9.48768329805   b = 6.08327625303   c = 3.60655512755

Area: T = 4.5
Perimeter: p = 19.17551467863
Semiperimeter: s = 9.58875733931

Angle ∠ A = α = 155.7722254682° = 155°46'20″ = 2.71987387275 rad
Angle ∠ B = β = 15.25551187031° = 15°15'18″ = 0.26662520492 rad
Angle ∠ C = γ = 8.97326266149° = 8°58'21″ = 0.1576601877 rad

Height: ha = 0.94986832981
Height: hb = 1.48795908857
Height: hc = 2.4966150883

Median: ma = 1.58111388301
Median: mb = 6.5
Median: mc = 7.76220873481

Inradius: r = 0.46993575544
Circumradius: R = 11.55990272563

Vertex coordinates: A[0; -3] B[-2; 0] C[1; -9]
Centroid: CG[-0.33333333333; -4]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[1.72109776993; 0.46993575544]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 24.2287745318° = 24°13'40″ = 2.71987387275 rad
∠ B' = β' = 164.7454881297° = 164°44'42″ = 0.26662520492 rad
∠ C' = γ' = 171.0277373385° = 171°1'39″ = 0.1576601877 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     