# 5 18 22 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 18   c = 22

Area: T = 29.76547022495
Perimeter: p = 45
Semiperimeter: s = 22.5

Angle ∠ A = α = 8.64658643504° = 8°38'45″ = 0.15108987996 rad
Angle ∠ B = β = 32.76437577589° = 32°45'50″ = 0.57218354482 rad
Angle ∠ C = γ = 138.5990377891° = 138°35'25″ = 2.41988584058 rad

Height: ha = 11.90658808998
Height: hb = 3.30771891388
Height: hc = 2.70658820227

Median: ma = 19.94436706752
Median: mb = 13.17219398723
Median: mc = 7.31443694192

Inradius: r = 1.32328756555
Circumradius: R = 16.63304368124

Vertex coordinates: A[22; 0] B[0; 0] C[4.20545454545; 2.70658820227]
Centroid: CG[8.73548484848; 0.90219606742]
Coordinates of the circumscribed circle: U[11; -12.47328276093]
Coordinates of the inscribed circle: I[4.5; 1.32328756555]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 171.354413565° = 171°21'15″ = 0.15108987996 rad
∠ B' = β' = 147.2366242241° = 147°14'10″ = 0.57218354482 rad
∠ C' = γ' = 41.41096221093° = 41°24'35″ = 2.41988584058 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    