# 4 9 11 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 9   c = 11

Area: T = 16.97105627485
Perimeter: p = 24
Semiperimeter: s = 12

Angle ∠ A = α = 20.05499757242° = 20°3' = 0.35499380913 rad
Angle ∠ B = β = 50.47988036414° = 50°28'44″ = 0.8811021326 rad
Angle ∠ C = γ = 109.4711220634° = 109°28'16″ = 1.91106332362 rad

Height: ha = 8.48552813742
Height: hb = 3.77112361663
Height: hc = 3.08655568634

Median: ma = 9.84988578018
Median: mb = 6.94662219947
Median: mc = 4.27220018727

Inradius: r = 1.41442135624
Circumradius: R = 5.83436309448

Vertex coordinates: A[11; 0] B[0; 0] C[2.54554545455; 3.08655568634]
Centroid: CG[4.51551515152; 1.02985189545]
Coordinates of the circumscribed circle: U[5.5; -1.94545436483]
Coordinates of the inscribed circle: I[3; 1.41442135624]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 159.9550024276° = 159°57' = 0.35499380913 rad
∠ B' = β' = 129.5211196359° = 129°31'16″ = 0.8811021326 rad
∠ C' = γ' = 70.52987793655° = 70°31'44″ = 1.91106332362 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.