Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 8.06222577483   b = 12.04215945788   c = 7.07110678119

Area: T = 27.5
Perimeter: p = 27.1754920139
Semiperimeter: s = 13.58774600695

Angle ∠ A = α = 40.23663583093° = 40°14'11″ = 0.70222569315 rad
Angle ∠ B = β = 105.2555118703° = 105°15'18″ = 1.83770483759 rad
Angle ∠ C = γ = 34.50985229877° = 34°30'31″ = 0.60222873461 rad

Height: ha = 6.82219104024
Height: hb = 4.5687501392
Height: hc = 7.77881745931

Median: ma = 9.01438781887
Median: mb = 4.61097722286
Median: mc = 9.61876920308

Inradius: r = 2.02439249911
Circumradius: R = 6.24106955535

Vertex coordinates: A[-3; 6] B[2; 1] C[9; 5]
Centroid: CG[2.66766666667; 4]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[-0.5521979543; 2.02439249911]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 139.7643641691° = 139°45'49″ = 0.70222569315 rad
∠ B' = β' = 74.74548812969° = 74°44'42″ = 1.83770483759 rad
∠ C' = γ' = 145.4911477012° = 145°29'29″ = 0.60222873461 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     