# 9 12 19 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 12   c = 19

Area: T = 41.95223539268
Perimeter: p = 40
Semiperimeter: s = 20

Angle ∠ A = α = 21.59325161782° = 21°35'33″ = 0.37768605011 rad
Angle ∠ B = β = 29.38546812566° = 29°23'5″ = 0.51328594376 rad
Angle ∠ C = γ = 129.0232802565° = 129°1'22″ = 2.25218727149 rad

Height: ha = 9.32327453171
Height: hb = 6.99220589878
Height: hc = 4.41660372555

Median: ma = 15.24397506541
Median: mb = 13.60114705087
Median: mc = 4.7176990566

Inradius: r = 2.09876176963
Circumradius: R = 12.22881577071

Vertex coordinates: A[19; 0] B[0; 0] C[7.84221052632; 4.41660372555]
Centroid: CG[8.94773684211; 1.47220124185]
Coordinates of the circumscribed circle: U[9.5; -7.69992104082]
Coordinates of the inscribed circle: I[8; 2.09876176963]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 158.4077483822° = 158°24'27″ = 0.37768605011 rad
∠ B' = β' = 150.6155318743° = 150°36'55″ = 0.51328594376 rad
∠ C' = γ' = 50.97771974348° = 50°58'38″ = 2.25218727149 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.