Triangle calculator VC

Please enter the coordinates of the three vertices

Acute scalene triangle.

Sides: a = 20.22437484162   b = 27.78548879789   c = 21.84403296678

Area: T = 219
Perimeter: p = 69.84989660629
Semiperimeter: s = 34.92444830314

Angle ∠ A = α = 46.20218330645° = 46°12'7″ = 0.80663741074 rad
Angle ∠ B = β = 82.5855369709° = 82°35'7″ = 1.44113866154 rad
Angle ∠ C = γ = 51.21327972265° = 51°12'46″ = 0.89438319308 rad

Height: ha = 21.65877061278
Height: hb = 15.76439649414
Height: hc = 20.05546423365

Median: ma = 22.85327897641
Median: mb = 15.81113883008
Median: mc = 21.70882933461

Inradius: r = 6.27106726339
Circumradius: R = 14.01095887732

Vertex coordinates: A[-2; -20] B[4; 1] C[-16; 4]
Centroid: CG[-4.66766666667; -5]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[0.81660464387; 6.27106726339]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 133.7988166936° = 133°47'53″ = 0.80663741074 rad
∠ B' = β' = 97.4154630291° = 97°24'53″ = 1.44113866154 rad
∠ C' = γ' = 128.7877202773° = 128°47'14″ = 0.89438319308 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     