Triangle calculator VC

Please enter the coordinates of the three vertices

Acute scalene triangle.

Sides: a = 3.16222776602   b = 3.60655512755   c = 2.23660679775

Area: T = 3.5
Perimeter: p = 9.00438969131
Semiperimeter: s = 4.50219484566

Angle ∠ A = α = 60.25551187031° = 60°15'18″ = 1.05216502125 rad
Angle ∠ B = β = 81.87698976458° = 81°52'12″ = 1.42988992722 rad
Angle ∠ C = γ = 37.87549836511° = 37°52'30″ = 0.66110431689 rad

Height: ha = 2.21435943621
Height: hb = 1.94114506868
Height: hc = 3.13304951685

Median: ma = 2.55495097568
Median: mb = 2.06215528128
Median: mc = 3.20215621187

Inradius: r = 0.77774411533
Circumradius: R = 1.82110783977

Vertex coordinates: A[-1; -1] B[-2; 1] C[1; 2]
Centroid: CG[-0.66766666667; 0.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[0.11110630219; 0.77774411533]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 119.7454881297° = 119°44'42″ = 1.05216502125 rad
∠ B' = β' = 98.13301023542° = 98°7'48″ = 1.42988992722 rad
∠ C' = γ' = 142.1255016349° = 142°7'30″ = 0.66110431689 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     