# 5 9 13 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 9   c = 13

Area: T = 16.06882139642
Perimeter: p = 27
Semiperimeter: s = 13.5

Angle ∠ A = α = 15.94223686056° = 15°56'33″ = 0.27882468227 rad
Angle ∠ B = β = 29.63106273936° = 29°37'50″ = 0.51771520074 rad
Angle ∠ C = γ = 134.4277004001° = 134°25'37″ = 2.34661938234 rad

Height: ha = 6.42772855857
Height: hb = 3.57107142143
Height: hc = 2.47220329176

Median: ma = 10.89772473589
Median: mb = 8.7610707734
Median: mc = 3.27987192622

Inradius: r = 1.19902380714
Circumradius: R = 9.10218205462

Vertex coordinates: A[13; 0] B[0; 0] C[4.34661538462; 2.47220329176]
Centroid: CG[5.78220512821; 0.82440109725]
Coordinates of the circumscribed circle: U[6.5; -6.37112743823]
Coordinates of the inscribed circle: I[4.5; 1.19902380714]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 164.0587631394° = 164°3'27″ = 0.27882468227 rad
∠ B' = β' = 150.3699372606° = 150°22'10″ = 0.51771520074 rad
∠ C' = γ' = 45.57329959992° = 45°34'23″ = 2.34661938234 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.