# 19.15 68.696 81.636 triangle

### Obtuse scalene triangle.

Sides: a = 19.15   b = 68.696   c = 81.636

Area: T = 526.223270341
Perimeter: p = 169.482
Semiperimeter: s = 84.741

Angle ∠ A = α = 10.81766263477° = 10°49' = 0.18987857437 rad
Angle ∠ B = β = 42.3155122853° = 42°18'54″ = 0.73985382172 rad
Angle ∠ C = γ = 126.8688250799° = 126°52'6″ = 2.21442686927 rad

Height: ha = 54.95879846904
Height: hb = 15.32203302495
Height: hc = 12.89219276645

Median: ma = 74.83438682082
Median: mb = 48.33300568384
Median: mc = 29.61111859607

Inradius: r = 6.21097768897
Circumradius: R = 51.02114001441

Vertex coordinates: A[81.636; 0] B[0; 0] C[14.16105332206; 12.89219276645]
Centroid: CG[31.93221777402; 4.29773092215]
Coordinates of the circumscribed circle: U[40.818; -30.61216668717]
Coordinates of the inscribed circle: I[16.045; 6.21097768897]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 169.1833373652° = 169°11' = 0.18987857437 rad
∠ B' = β' = 137.6854877147° = 137°41'6″ = 0.73985382172 rad
∠ C' = γ' = 53.13217492006° = 53°7'54″ = 2.21442686927 rad

# How did we calculate this triangle?

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. ### 1. The triangle circumference is the sum of the lengths of its three sides ### 2. Semiperimeter of the triangle ### 3. The triangle area using Heron's formula ### 4. Calculate the heights of the triangle from its area. ### 5. Calculation of the inner angles of the triangle using a Law of Cosines    