# 15 19 30 triangle

### Obtuse scalene triangle.

Sides: a = 15   b = 19   c = 30

Area: T = 118.9298549979
Perimeter: p = 64
Semiperimeter: s = 32

Angle ∠ A = α = 24.66438107936° = 24°39'50″ = 0.43304647044 rad
Angle ∠ B = β = 31.90989763008° = 31°54'32″ = 0.55769166974 rad
Angle ∠ C = γ = 123.4277212906° = 123°25'38″ = 2.15442112518 rad

Height: ha = 15.85771399971
Height: hb = 12.51987947346
Height: hc = 7.92985699986

Median: ma = 23.96435139326
Median: mb = 21.73113138121
Median: mc = 8.24662112512

Inradius: r = 3.71765171868
Circumradius: R = 17.97329762146

Vertex coordinates: A[30; 0] B[0; 0] C[12.73333333333; 7.92985699986]
Centroid: CG[14.24444444444; 2.64328566662]
Coordinates of the circumscribed circle: U[15; -9.90109026866]
Coordinates of the inscribed circle: I[13; 3.71765171868]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 155.3366189206° = 155°20'10″ = 0.43304647044 rad
∠ B' = β' = 148.0911023699° = 148°5'28″ = 0.55769166974 rad
∠ C' = γ' = 56.57327870944° = 56°34'22″ = 2.15442112518 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    