# 4 18 19 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 18   c = 19

Area: T = 35.61551302118
Perimeter: p = 41
Semiperimeter: s = 20.5

Angle ∠ A = α = 12.02113180101° = 12°1'17″ = 0.21098115797 rad
Angle ∠ B = β = 69.59331433428° = 69°35'35″ = 1.21546294881 rad
Angle ∠ C = γ = 98.38655386471° = 98°23'8″ = 1.71771515857 rad

Height: ha = 17.80875651059
Height: hb = 3.95772366902
Height: hc = 3.74989610749

Median: ma = 18.3988369493
Median: mb = 10.36882206767
Median: mc = 8.93302855497

Inradius: r = 1.7377323425
Circumradius: R = 9.60326603853

Vertex coordinates: A[19; 0] B[0; 0] C[1.39547368421; 3.74989610749]
Centroid: CG[6.7988245614; 1.25496536916]
Coordinates of the circumscribed circle: U[9.5; -1.44003879728]
Coordinates of the inscribed circle: I[2.5; 1.7377323425]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 167.979868199° = 167°58'43″ = 0.21098115797 rad
∠ B' = β' = 110.4076856657° = 110°24'25″ = 1.21546294881 rad
∠ C' = γ' = 81.61444613529° = 81°36'52″ = 1.71771515857 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.