Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 18.02877563773   b = 8.6022325267   c = 10.44403065089

Area: T = 27.5
Perimeter: p = 37.07703881533
Semiperimeter: s = 18.53551940766

Angle ∠ A = α = 142.2376922026° = 142°14'13″ = 2.48325026073 rad
Angle ∠ B = β = 16.9910823292° = 16°59'27″ = 0.29765458091 rad
Angle ∠ C = γ = 20.7722254682° = 20°46'20″ = 0.36325442373 rad

Height: ha = 3.05108510792
Height: hb = 6.39436201309
Height: hc = 5.26880445687

Median: ma = 3.20215621187
Median: mb = 14.08990028036
Median: mc = 13.12444047484

Inradius: r = 1.484366399
Circumradius: R = 14.71989931833

Vertex coordinates: A[3; 5] B[6; -5] C[-4; 10]
Centroid: CG[1.66766666667; 3.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[4.85656276038; 1.484366399]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 37.7633077974° = 37°45'47″ = 2.48325026073 rad
∠ B' = β' = 163.0099176708° = 163°33″ = 0.29765458091 rad
∠ C' = γ' = 159.2287745318° = 159°13'40″ = 0.36325442373 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     