Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 6.40331242374   b = 15.65224758425   c = 9.48768329805

Area: T = 10.5
Perimeter: p = 31.54224330604
Semiperimeter: s = 15.77112165302

Angle ∠ A = α = 8.13301023542° = 8°7'48″ = 0.14218970546 rad
Angle ∠ B = β = 159.7755140569° = 159°46'31″ = 2.78986022658 rad
Angle ∠ C = γ = 12.0954757077° = 12°5'41″ = 0.21110933332 rad

Height: ha = 3.28796489997
Height: hb = 1.34216407865
Height: hc = 2.21435943621

Median: ma = 12.5439936204
Median: mb = 2.06215528128
Median: mc = 10.97772492001

Inradius: r = 0.66657698206
Circumradius: R = 22.63884628453

Vertex coordinates: A[1; -5] B[4; 4] C[8; 9]
Centroid: CG[4.33333333333; 2.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-1.80770895131; 0.66657698206]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 171.8769897646° = 171°52'12″ = 0.14218970546 rad
∠ B' = β' = 20.22548594312° = 20°13'29″ = 2.78986022658 rad
∠ C' = γ' = 167.9055242923° = 167°54'19″ = 0.21110933332 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     