# 6 11 13 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 11   c = 13

Area: T = 32.86333534503
Perimeter: p = 30
Semiperimeter: s = 15

Angle ∠ A = α = 27.36330618223° = 27°21'47″ = 0.47875755222 rad
Angle ∠ B = β = 57.42110296072° = 57°25'16″ = 1.00221860265 rad
Angle ∠ C = γ = 95.21659085705° = 95°12'57″ = 1.66218311048 rad

Height: ha = 10.95444511501
Height: hb = 5.97551551728
Height: hc = 5.05659005308

Median: ma = 11.66219037897
Median: mb = 8.5
Median: mc = 6.02107972894

Inradius: r = 2.191089023
Circumradius: R = 6.52770271436

Vertex coordinates: A[13; 0] B[0; 0] C[3.23107692308; 5.05659005308]
Centroid: CG[5.41102564103; 1.68553001769]
Coordinates of the circumscribed circle: U[6.5; -0.5933366104]
Coordinates of the inscribed circle: I[4; 2.191089023]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.6376938178° = 152°38'13″ = 0.47875755222 rad
∠ B' = β' = 122.5798970393° = 122°34'44″ = 1.00221860265 rad
∠ C' = γ' = 84.78440914295° = 84°47'3″ = 1.66218311048 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    