# 3 19 20 triangle

### Obtuse scalene triangle.

Sides: a = 3   b = 19   c = 20

Area: T = 27.49554541697
Perimeter: p = 42
Semiperimeter: s = 21

Angle ∠ A = α = 8.32106551878° = 8°19'14″ = 0.14552228289 rad
Angle ∠ B = β = 66.42218215218° = 66°25'19″ = 1.15992794807 rad
Angle ∠ C = γ = 105.258752329° = 105°15'27″ = 1.83770903439 rad

Height: ha = 18.33303027798
Height: hb = 2.89442583337
Height: hc = 2.7549545417

Median: ma = 19.44986503388
Median: mb = 10.68987791632
Median: mc = 9.22195444573

Inradius: r = 1.30993073414
Circumradius: R = 10.36553497862

Vertex coordinates: A[20; 0] B[0; 0] C[1.2; 2.7549545417]
Centroid: CG[7.06766666667; 0.9176515139]
Coordinates of the circumscribed circle: U[10; -2.72877236279]
Coordinates of the inscribed circle: I[2; 1.30993073414]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 171.6799344812° = 171°40'46″ = 0.14552228289 rad
∠ B' = β' = 113.5788178478° = 113°34'41″ = 1.15992794807 rad
∠ C' = γ' = 74.74224767095° = 74°44'33″ = 1.83770903439 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.