# 8 14 20 triangle

### Obtuse scalene triangle.

Sides: a = 8   b = 14   c = 20

Area: T = 43.71549859888
Perimeter: p = 42
Semiperimeter: s = 21

Angle ∠ A = α = 18.19548723388° = 18°11'42″ = 0.31875604293 rad
Angle ∠ B = β = 33.12329402077° = 33°7'23″ = 0.57881043646 rad
Angle ∠ C = γ = 128.6822187453° = 128°40'56″ = 2.24659278597 rad

Height: ha = 10.92987464972
Height: hb = 6.24549979984
Height: hc = 4.37114985989

Median: ma = 16.79328556237
Median: mb = 13.52877492585
Median: mc = 5.47772255751

Inradius: r = 2.08216659995
Circumradius: R = 12.81102523044

Vertex coordinates: A[20; 0] B[0; 0] C[6.7; 4.37114985989]
Centroid: CG[8.9; 1.45771661996]
Coordinates of the circumscribed circle: U[10; -8.00664076903]
Coordinates of the inscribed circle: I[7; 2.08216659995]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.8055127661° = 161°48'18″ = 0.31875604293 rad
∠ B' = β' = 146.8777059792° = 146°52'37″ = 0.57881043646 rad
∠ C' = γ' = 51.31878125465° = 51°19'4″ = 2.24659278597 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    