Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 2.44994897428   b = 4.12331056256   c = 1.73220508076

Area: T = 0.70771067812
Perimeter: p = 8.3054646176
Semiperimeter: s = 4.1522323088

Angle ∠ A = α = 11.4221753659° = 11°25'18″ = 0.19993472077 rad
Angle ∠ B = β = 160.5298779366° = 160°31'44″ = 2.80217557441 rad
Angle ∠ C = γ = 8.04994669755° = 8°2'58″ = 0.14404897018 rad

Height: ha = 0.57773502692
Height: hb = 0.34329971703
Height: hc = 0.81664965809

Median: ma = 2.91554759474
Median: mb = 0.5
Median: mc = 3.27987192622

Inradius: r = 0.17702918502
Circumradius: R = 6.18546584384

Vertex coordinates: A[-1; 2; 0] B[0; 3; 1] C[1; 4; 3]
Centroid: CG[0; 3; 1.33333333333]
Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 168.5788246341° = 168°34'42″ = 0.19993472077 rad
∠ B' = β' = 19.47112206345° = 19°28'16″ = 2.80217557441 rad
∠ C' = γ' = 171.9510533024° = 171°57'2″ = 0.14404897018 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     