# 8 11 13 triangle

### Acute scalene triangle.

Sides: a = 8   b = 11   c = 13

Area: T = 43.81878046004
Perimeter: p = 32
Semiperimeter: s = 16

Angle ∠ A = α = 37.79548789633° = 37°47'42″ = 0.66596450783 rad
Angle ∠ B = β = 57.42110296072° = 57°25'16″ = 1.00221860265 rad
Angle ∠ C = γ = 84.78440914295° = 84°47'3″ = 1.48797615488 rad

Height: ha = 10.95444511501
Height: hb = 7.96768735637
Height: hc = 6.74112007078

Median: ma = 11.35878166916
Median: mb = 9.28770878105
Median: mc = 7.08987234394

Inradius: r = 2.73986127875
Circumradius: R = 6.52770271436

Vertex coordinates: A[13; 0] B[0; 0] C[4.30876923077; 6.74112007078]
Centroid: CG[5.76992307692; 2.24770669026]
Coordinates of the circumscribed circle: U[6.5; 0.5933366104]
Coordinates of the inscribed circle: I[5; 2.73986127875]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.2055121037° = 142°12'18″ = 0.66596450783 rad
∠ B' = β' = 122.5798970393° = 122°34'44″ = 1.00221860265 rad
∠ C' = γ' = 95.21659085705° = 95°12'57″ = 1.48797615488 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.