# 12 22 28 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 22   c = 28

Area: T = 126.1077097342
Perimeter: p = 62
Semiperimeter: s = 31

Angle ∠ A = α = 24.17695751524° = 24°10'10″ = 0.42218386652 rad
Angle ∠ B = β = 48.64656289465° = 48°38'44″ = 0.84990263918 rad
Angle ∠ C = γ = 107.1854795901° = 107°11'5″ = 1.87107275966 rad

Height: ha = 21.0187849557
Height: hb = 11.46442815765
Height: hc = 9.00876498101

Median: ma = 24.45440385213
Median: mb = 18.52202591775
Median: mc = 10.86327804912

Inradius: r = 4.0687970882
Circumradius: R = 14.65442108966

Vertex coordinates: A[28; 0] B[0; 0] C[7.92985714286; 9.00876498101]
Centroid: CG[11.97661904762; 3.00325499367]
Coordinates of the circumscribed circle: U[14; -4.33296532194]
Coordinates of the inscribed circle: I[9; 4.0687970882]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 155.8330424848° = 155°49'50″ = 0.42218386652 rad
∠ B' = β' = 131.3544371054° = 131°21'16″ = 0.84990263918 rad
∠ C' = γ' = 72.81552040989° = 72°48'55″ = 1.87107275966 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.