# 13 26 28 triangle

### Acute scalene triangle.

Sides: a = 13   b = 26   c = 28

Area: T = 168.3110538886
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 27.54215404525° = 27°32'30″ = 0.4810690562 rad
Angle ∠ B = β = 67.63656831745° = 67°38'8″ = 1.18804653632 rad
Angle ∠ C = γ = 84.82327763731° = 84°49'22″ = 1.48804367284 rad

Height: ha = 25.89439290593
Height: hb = 12.94769645297
Height: hc = 12.0222181349

Median: ma = 26.22549880839
Median: mb = 17.53656779168
Median: mc = 15.05499169433

Inradius: r = 5.02441951906
Circumradius: R = 14.05773490862

Vertex coordinates: A[28; 0] B[0; 0] C[4.94664285714; 12.0222181349]
Centroid: CG[10.98221428571; 4.0077393783]
Coordinates of the circumscribed circle: U[14; 1.2688488601]
Coordinates of the inscribed circle: I[7.5; 5.02441951906]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.4588459548° = 152°27'30″ = 0.4810690562 rad
∠ B' = β' = 112.3644316826° = 112°21'52″ = 1.18804653632 rad
∠ C' = γ' = 95.17772236269° = 95°10'38″ = 1.48804367284 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.