# 7 9 11 triangle

### Acute scalene triangle.

Sides: a = 7   b = 9   c = 11

Area: T = 31.42195400985
Perimeter: p = 27
Semiperimeter: s = 13.5

Angle ∠ A = α = 39.40105687537° = 39°24'2″ = 0.68876696519 rad
Angle ∠ B = β = 54.69554750044° = 54°41'44″ = 0.95546161248 rad
Angle ∠ C = γ = 85.90439562418° = 85°54'14″ = 1.49993068769 rad

Height: ha = 8.97770114567
Height: hb = 6.98221200219
Height: hc = 5.71326436543

Median: ma = 9.42107218407
Median: mb = 8.04767384697
Median: mc = 5.89549130613

Inradius: r = 2.32773733406
Circumradius: R = 5.51440845301

Vertex coordinates: A[11; 0] B[0; 0] C[4.04554545455; 5.71326436543]
Centroid: CG[5.01551515152; 1.90442145514]
Coordinates of the circumscribed circle: U[5.5; 0.39438631807]
Coordinates of the inscribed circle: I[4.5; 2.32773733406]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.5999431246° = 140°35'58″ = 0.68876696519 rad
∠ B' = β' = 125.3054524996° = 125°18'16″ = 0.95546161248 rad
∠ C' = γ' = 94.09660437582° = 94°5'46″ = 1.49993068769 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.