Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse scalene triangle.

Sides: a = 8.54440037453   b = 13.45436240471   c = 18.38547763109

Area: T = 53.5
Perimeter: p = 40.38224041032
Semiperimeter: s = 20.19112020516

Angle ∠ A = α = 25.63326524522° = 25°37'58″ = 0.44773741813 rad
Angle ∠ B = β = 42.93661802715° = 42°56'10″ = 0.7499377714 rad
Angle ∠ C = γ = 111.4311167276° = 111°25'52″ = 1.94548407583 rad

Height: ha = 12.523340275
Height: hb = 7.95332473648
Height: hc = 5.82200327375

Median: ma = 15.5322224567
Median: mb = 12.65989889012
Median: mc = 6.51992024052

Inradius: r = 2.65496688936
Circumradius: R = 9.87551862259

Vertex coordinates: A[-10; -3] B[7; 4] C[-1; 7]
Centroid: CG[-1.33333333333; 2.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[2.84877749791; 2.65496688936]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.3677347548° = 154°22'2″ = 0.44773741813 rad
∠ B' = β' = 137.0643819728° = 137°3'50″ = 0.7499377714 rad
∠ C' = γ' = 68.56988327238° = 68°34'8″ = 1.94548407583 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     