# 11 22 28 triangle

### Obtuse scalene triangle.

Sides: a = 11   b = 22   c = 28

Area: T = 112.4210805459
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 21.40877436432° = 21°24'28″ = 0.3743635612 rad
Angle ∠ B = β = 46.88768325263° = 46°53'13″ = 0.81883296034 rad
Angle ∠ C = γ = 111.705542383° = 111°42'20″ = 1.95496274382 rad

Height: ha = 20.44401464471
Height: hb = 10.22200732235
Height: hc = 8.03300575328

Median: ma = 24.57113247506
Median: mb = 18.2077141456
Median: mc = 10.32198837203

Inradius: r = 3.68659280478
Circumradius: R = 15.06883851898

Vertex coordinates: A[28; 0] B[0; 0] C[7.51878571429; 8.03300575328]
Centroid: CG[11.83992857143; 2.67766858443]
Coordinates of the circumscribed circle: U[14; -5.5732811878]
Coordinates of the inscribed circle: I[8.5; 3.68659280478]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 158.5922256357° = 158°35'32″ = 0.3743635612 rad
∠ B' = β' = 133.1133167474° = 133°6'47″ = 0.81883296034 rad
∠ C' = γ' = 68.29545761695° = 68°17'40″ = 1.95496274382 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    