Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 23.34552350599   b = 13.4166407865   c = 11.18803398875

Area: T = 45
Perimeter: p = 47.94219828124
Semiperimeter: s = 23.97109914062

Angle ∠ A = α = 143.1330102354° = 143°7'48″ = 2.49880915448 rad
Angle ∠ B = β = 20.17106534119° = 20°10'14″ = 0.35220443143 rad
Angle ∠ C = γ = 16.6999244234° = 16°41'57″ = 0.29114567945 rad

Height: ha = 3.85551764319
Height: hb = 6.70882039325
Height: hc = 8.0549844719

Median: ma = 4.03111288741
Median: mb = 17.02993863659
Median: mc = 18.22002747232

Inradius: r = 1.8777269039
Circumradius: R = 19.45443625499

Vertex coordinates: A[-3; 3] B[7; 8] C[-9; -9]
Centroid: CG[-1.66766666667; 0.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[5.11103434949; 1.8777269039]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 36.87698976458° = 36°52'12″ = 2.49880915448 rad
∠ B' = β' = 159.8299346588° = 159°49'46″ = 0.35220443143 rad
∠ C' = γ' = 163.3010755766° = 163°18'3″ = 0.29114567945 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     