# 9 9 11 triangle

### Acute isosceles triangle.

Sides: a = 9   b = 9   c = 11

Area: T = 39.18114688341
Perimeter: p = 29
Semiperimeter: s = 14.5

Angle ∠ A = α = 52.33301130357° = 52°19'48″ = 0.91333327704 rad
Angle ∠ B = β = 52.33301130357° = 52°19'48″ = 0.91333327704 rad
Angle ∠ C = γ = 75.34397739287° = 75°20'23″ = 1.31549271128 rad

Height: ha = 8.70769930743
Height: hb = 8.70769930743
Height: hc = 7.12439034244

Median: ma = 8.98661003778
Median: mb = 8.98661003778
Median: mc = 7.12439034244

Inradius: r = 2.70221702644
Circumradius: R = 5.68550854914

Vertex coordinates: A[11; 0] B[0; 0] C[5.5; 7.12439034244]
Centroid: CG[5.5; 2.37546344748]
Coordinates of the circumscribed circle: U[5.5; 1.4398817933]
Coordinates of the inscribed circle: I[5.5; 2.70221702644]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 127.6769886964° = 127°40'12″ = 0.91333327704 rad
∠ B' = β' = 127.6769886964° = 127°40'12″ = 0.91333327704 rad
∠ C' = γ' = 104.6660226071° = 104°39'37″ = 1.31549271128 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.