# 6 9 13 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 9   c = 13

Area: T = 23.66443191324
Perimeter: p = 28
Semiperimeter: s = 14

Angle ∠ A = α = 23.86109433465° = 23°51'39″ = 0.4166452024 rad
Angle ∠ B = β = 37.35768519729° = 37°21'25″ = 0.65220000651 rad
Angle ∠ C = γ = 118.7822204681° = 118°46'56″ = 2.07331405645 rad

Height: ha = 7.88881063775
Height: hb = 5.2598737585
Height: hc = 3.64106644819

Median: ma = 10.77703296143
Median: mb = 9.06991785736
Median: mc = 4.03111288741

Inradius: r = 1.69903085095
Circumradius: R = 7.41662285852

Vertex coordinates: A[13; 0] B[0; 0] C[4.76992307692; 3.64106644819]
Centroid: CG[5.92330769231; 1.21435548273]
Coordinates of the circumscribed circle: U[6.5; -3.57107767262]
Coordinates of the inscribed circle: I[5; 1.69903085095]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.1399056653° = 156°8'21″ = 0.4166452024 rad
∠ B' = β' = 142.6433148027° = 142°38'35″ = 0.65220000651 rad
∠ C' = γ' = 61.21877953194° = 61°13'4″ = 2.07331405645 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.