# 3 11 13 triangle

### Obtuse scalene triangle.

Sides: a = 3   b = 11   c = 13

Area: T = 13.3111179512
Perimeter: p = 27
Semiperimeter: s = 13.5

Angle ∠ A = α = 10.72993735799° = 10°43'46″ = 0.18772628956 rad
Angle ∠ B = β = 43.04990798002° = 43°2'57″ = 0.75113481825 rad
Angle ∠ C = γ = 126.222154662° = 126°13'18″ = 2.20329815755 rad

Height: ha = 8.87441196746
Height: hb = 2.42202144567
Height: hc = 2.04878737711

Median: ma = 11.94878031453
Median: mb = 7.66548548584
Median: mc = 4.77696960071

Inradius: r = 0.98660132972
Circumradius: R = 8.05771372284

Vertex coordinates: A[13; 0] B[0; 0] C[2.19223076923; 2.04878737711]
Centroid: CG[5.06441025641; 0.68326245904]
Coordinates of the circumscribed circle: U[6.5; -4.7611035635]
Coordinates of the inscribed circle: I[2.5; 0.98660132972]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 169.271062642° = 169°16'14″ = 0.18772628956 rad
∠ B' = β' = 136.95109202° = 136°57'3″ = 0.75113481825 rad
∠ C' = γ' = 53.77884533802° = 53°46'42″ = 2.20329815755 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.