# 12 26 28 triangle

### Acute scalene triangle.

Sides: a = 12   b = 26   c = 28

Area: T = 155.7440168229
Perimeter: p = 66
Semiperimeter: s = 33

Angle ∠ A = α = 25.33216750167° = 25°19'54″ = 0.44221211341 rad
Angle ∠ B = β = 67.9765687163° = 67°58'32″ = 1.18663995523 rad
Angle ∠ C = γ = 86.69326378203° = 86°41'34″ = 1.51330719672 rad

Height: ha = 25.95766947048
Height: hb = 11.98800129407
Height: hc = 11.12442977306

Median: ma = 26.34438797446
Median: mb = 17.17655640373
Median: mc = 14.62987388383

Inradius: r = 4.71993990372
Circumradius: R = 14.02333571392

Vertex coordinates: A[28; 0] B[0; 0] C[4.5; 11.12442977306]
Centroid: CG[10.83333333333; 3.70880992435]
Coordinates of the circumscribed circle: U[14; 0.8099039835]
Coordinates of the inscribed circle: I[7; 4.71993990372]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.6688324983° = 154°40'6″ = 0.44221211341 rad
∠ B' = β' = 112.0244312837° = 112°1'28″ = 1.18663995523 rad
∠ C' = γ' = 93.30773621797° = 93°18'26″ = 1.51330719672 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.