# 5 15 19 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 15   c = 19

Area: T = 25.22327575812
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 10.19551720375° = 10°11'43″ = 0.17879393199 rad
Angle ∠ B = β = 32.07334123921° = 32°4'24″ = 0.56597866486 rad
Angle ∠ C = γ = 137.731141557° = 137°43'53″ = 2.40438666851 rad

Height: ha = 10.08991030325
Height: hb = 3.36330343442
Height: hc = 2.65550271138

Median: ma = 16.93436942219
Median: mb = 11.69440155635
Median: mc = 5.89549130613

Inradius: r = 1.29334747478
Circumradius: R = 14.12441495444

Vertex coordinates: A[19; 0] B[0; 0] C[4.23768421053; 2.65550271138]
Centroid: CG[7.74656140351; 0.88550090379]
Coordinates of the circumscribed circle: U[9.5; -10.45218706629]
Coordinates of the inscribed circle: I[4.5; 1.29334747478]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 169.8054827963° = 169°48'17″ = 0.17879393199 rad
∠ B' = β' = 147.9276587608° = 147°55'36″ = 0.56597866486 rad
∠ C' = γ' = 42.26985844296° = 42°16'7″ = 2.40438666851 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    