# 6 16 20 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 16   c = 20

Area: T = 39.6866269666
Perimeter: p = 42
Semiperimeter: s = 21

Angle ∠ A = α = 14.36215115629° = 14°21'41″ = 0.25106556623 rad
Angle ∠ B = β = 41.41096221093° = 41°24'35″ = 0.72327342478 rad
Angle ∠ C = γ = 124.2298866328° = 124°13'44″ = 2.16882027434 rad

Height: ha = 13.22987565553
Height: hb = 4.96107837082
Height: hc = 3.96986269666

Median: ma = 17.86105710995
Median: mb = 12.4109673646
Median: mc = 6.78223299831

Inradius: r = 1.8989822365
Circumradius: R = 12.09548631363

Vertex coordinates: A[20; 0] B[0; 0] C[4.5; 3.96986269666]
Centroid: CG[8.16766666667; 1.32328756555]
Coordinates of the circumscribed circle: U[10; -6.80333605142]
Coordinates of the inscribed circle: I[5; 1.8989822365]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 165.6388488437° = 165°38'19″ = 0.25106556623 rad
∠ B' = β' = 138.5990377891° = 138°35'25″ = 0.72327342478 rad
∠ C' = γ' = 55.77111336722° = 55°46'16″ = 2.16882027434 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.