# 11 15 19 triangle

### Obtuse scalene triangle.

Sides: a = 11   b = 15   c = 19

Area: T = 82.41547286594
Perimeter: p = 45
Semiperimeter: s = 22.5

Angle ∠ A = α = 35.33545017918° = 35°20'4″ = 0.61767033958 rad
Angle ∠ B = β = 52.06602469431° = 52°3'37″ = 0.90986227186 rad
Angle ∠ C = γ = 92.60552512651° = 92°36'19″ = 1.61662665392 rad

Height: ha = 14.98444961199
Height: hb = 10.98986304879
Height: hc = 8.67552345957

Median: ma = 16.21095650774
Median: mb = 13.59222772191
Median: mc = 9.09767026993

Inradius: r = 3.66328768293
Circumradius: R = 9.51098292835

Vertex coordinates: A[19; 0] B[0; 0] C[6.76331578947; 8.67552345957]
Centroid: CG[8.58877192982; 2.89217448652]
Coordinates of the circumscribed circle: U[9.5; -0.43222649674]
Coordinates of the inscribed circle: I[7.5; 3.66328768293]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 144.6655498208° = 144°39'56″ = 0.61767033958 rad
∠ B' = β' = 127.9439753057° = 127°56'23″ = 0.90986227186 rad
∠ C' = γ' = 87.39547487349° = 87°23'41″ = 1.61662665392 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    