# 12 13 19 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 13   c = 19

Area: T = 77.0711395472
Perimeter: p = 44
Semiperimeter: s = 22

Angle ∠ A = α = 38.61332185386° = 38°36'48″ = 0.67439277983 rad
Angle ∠ B = β = 42.5376898363° = 42°32'13″ = 0.742240893 rad
Angle ∠ C = γ = 98.85498830984° = 98°51' = 1.72552559253 rad

Height: ha = 12.84552325787
Height: hb = 11.85771377649
Height: hc = 8.11327784707

Median: ma = 15.13327459504
Median: mb = 14.5
Median: mc = 8.1399410298

Inradius: r = 3.50332452487
Circumradius: R = 9.61444619604

Vertex coordinates: A[19; 0] B[0; 0] C[8.84221052632; 8.11327784707]
Centroid: CG[9.28107017544; 2.70442594902]
Coordinates of the circumscribed circle: U[9.5; -1.47991479939]
Coordinates of the inscribed circle: I[9; 3.50332452487]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.3876781461° = 141°23'12″ = 0.67439277983 rad
∠ B' = β' = 137.4633101637° = 137°27'47″ = 0.742240893 rad
∠ C' = γ' = 81.15501169016° = 81°9' = 1.72552559253 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.