# 6 18 20 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 18   c = 20

Area: T = 53.06659966457
Perimeter: p = 44
Semiperimeter: s = 22

Angle ∠ A = α = 17.14662099989° = 17°8'46″ = 0.29992578187 rad
Angle ∠ B = β = 62.18218607153° = 62°10'55″ = 1.08552782045 rad
Angle ∠ C = γ = 100.6721929286° = 100°40'19″ = 1.75770566304 rad

Height: ha = 17.68986655486
Height: hb = 5.89662218495
Height: hc = 5.30765996646

Median: ma = 18.78882942281
Median: mb = 11.70546999107
Median: mc = 8.944427191

Inradius: r = 2.41220907566
Circumradius: R = 10.17660078795

Vertex coordinates: A[20; 0] B[0; 0] C[2.8; 5.30765996646]
Centroid: CG[7.6; 1.76988665549]
Coordinates of the circumscribed circle: U[10; -1.88444459036]
Coordinates of the inscribed circle: I[4; 2.41220907566]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.8543790001° = 162°51'14″ = 0.29992578187 rad
∠ B' = β' = 117.8188139285° = 117°49'5″ = 1.08552782045 rad
∠ C' = γ' = 79.32880707142° = 79°19'41″ = 1.75770566304 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.