Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 18.43990889146   b = 2.23660679775   c = 19.92548588452

Area: T = 16
Perimeter: p = 40.66000157373
Semiperimeter: s = 20.33000078686

Angle ∠ A = α = 45.90993804492° = 45°54'34″ = 0.80112698464 rad
Angle ∠ B = β = 4.99767606646° = 4°59'48″ = 0.08772099255 rad
Angle ∠ C = γ = 129.0943858886° = 129°5'38″ = 2.25331128817 rad

Height: ha = 1.73554436625
Height: hb = 14.3110835056
Height: hc = 1.60660339623

Median: ma = 10.77703296143
Median: mb = 19.16437678967
Median: mc = 8.55986213843

Inradius: r = 0.78881770344
Circumradius: R = 12.83662964991

Vertex coordinates: A[5; -10] B[-1; 9] C[3; -9]
Centroid: CG[2.33333333333; -3.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[9.01547748308; 0.78881770344]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.0910619551° = 134°5'26″ = 0.80112698464 rad
∠ B' = β' = 175.0033239335° = 175°12″ = 0.08772099255 rad
∠ C' = γ' = 50.90661411138° = 50°54'22″ = 2.25331128817 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     