Triangle calculator VC

Please enter the coordinates of the three vertices

Acute isosceles triangle.

Sides: a = 4.24326406871   b = 3.74216573868   c = 3.74216573868

Area: T = 6.53883484153
Perimeter: p = 11.72659554607
Semiperimeter: s = 5.86329777303

Angle ∠ A = α = 69.07551675724° = 69°4'31″ = 1.20655891055 rad
Angle ∠ B = β = 55.46224162138° = 55°27'45″ = 0.9688001774 rad
Angle ∠ C = γ = 55.46224162138° = 55°27'45″ = 0.9688001774 rad

Height: ha = 3.08222070015
Height: hb = 3.49548942351
Height: hc = 3.49548942351

Median: ma = 3.08222070015
Median: mb = 3.53655339059
Median: mc = 3.53655339059

Inradius: r = 1.11551924357
Circumradius: R = 2.27110998958

Vertex coordinates: A[2; -2; -1] B[-1; 0; -2] C[0; -1; 2]
Centroid: CG[0.33333333333; -1; -0.33333333333]
Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 110.9254832428° = 110°55'29″ = 1.20655891055 rad
∠ B' = β' = 124.5387583786° = 124°32'15″ = 0.9688001774 rad
∠ C' = γ' = 124.5387583786° = 124°32'15″ = 0.9688001774 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     