# 13 17 26 triangle

### Obtuse scalene triangle.

Sides: a = 13   b = 17   c = 26

Area: T = 96.12549187256
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 25.78223912575° = 25°46'57″ = 0.45499876165 rad
Angle ∠ B = β = 34.66656480821° = 34°39'56″ = 0.60550296964 rad
Angle ∠ C = γ = 119.552196066° = 119°33'7″ = 2.08765753407 rad

Height: ha = 14.78884490347
Height: hb = 11.30988139677
Height: hc = 7.39442245174

Median: ma = 20.98221352584
Median: mb = 18.71549672722
Median: mc = 7.74659666924

Inradius: r = 3.43330328116
Circumradius: R = 14.94440958603

Vertex coordinates: A[26; 0] B[0; 0] C[10.69223076923; 7.39442245174]
Centroid: CG[12.23107692308; 2.46547415058]
Coordinates of the circumscribed circle: U[13; -7.37106174153]
Coordinates of the inscribed circle: I[11; 3.43330328116]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.2187608743° = 154°13'3″ = 0.45499876165 rad
∠ B' = β' = 145.3344351918° = 145°20'4″ = 0.60550296964 rad
∠ C' = γ' = 60.44880393396° = 60°26'53″ = 2.08765753407 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.