# 6 9 11 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 9   c = 11

Area: T = 26.98114751265
Perimeter: p = 26
Semiperimeter: s = 13

Angle ∠ A = α = 33.03301516046° = 33°1'49″ = 0.57664848979 rad
Angle ∠ B = β = 54.84772970332° = 54°50'50″ = 0.9577265919 rad
Angle ∠ C = γ = 92.12325513621° = 92°7'21″ = 1.60878418366 rad

Height: ha = 8.99438250422
Height: hb = 5.99658833614
Height: hc = 4.90657227503

Median: ma = 9.59216630466
Median: mb = 7.63221687612
Median: mc = 5.31550729064

Inradius: r = 2.07554980867
Circumradius: R = 5.50437761762

Vertex coordinates: A[11; 0] B[0; 0] C[3.45545454545; 4.90657227503]
Centroid: CG[4.81881818182; 1.63552409168]
Coordinates of the circumscribed circle: U[5.5; -0.20438435621]
Coordinates of the inscribed circle: I[4; 2.07554980867]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.9769848395° = 146°58'11″ = 0.57664848979 rad
∠ B' = β' = 125.1532702967° = 125°9'10″ = 0.9577265919 rad
∠ C' = γ' = 87.87774486379° = 87°52'39″ = 1.60878418366 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    