# Triangle calculator VC

Please enter the coordinates of the three vertices

### Obtuse scalene triangle.

Sides: a = 11.18803398875   b = 12.53299640861   c = 21.4010934559

Area: T = 54.5
Perimeter: p = 45.11112385327
Semiperimeter: s = 22.55656192663

Angle ∠ A = α = 23.98441837026° = 23°59'3″ = 0.4198602974 rad
Angle ∠ B = β = 27.10105101626° = 27°6'2″ = 0.47329931313 rad
Angle ∠ C = γ = 128.9155306135° = 128°54'55″ = 2.25499965483 rad

Height: ha = 9.74992563819
Height: hb = 8.69991470407
Height: hc = 5.09332355173

Median: ma = 16.62107701386
Median: mb = 15.88223801743
Median: mc = 5.14878150705

Inradius: r = 2.41662493327
Circumradius: R = 13.75224817756

Vertex coordinates: A[4; 7] B[-9; -10] C[-7; 1]
Centroid: CG[-4; -0.66766666667]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[4.722166154; 2.41662493327]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.0165816297° = 156°57″ = 0.4198602974 rad
∠ B' = β' = 152.8999489837° = 152°53'58″ = 0.47329931313 rad
∠ C' = γ' = 51.08546938653° = 51°5'5″ = 2.25499965483 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    