# 9 9 14 triangle

### Obtuse isosceles triangle.

Sides: a = 9   b = 9   c = 14

Area: T = 39.59879797464
Perimeter: p = 32
Semiperimeter: s = 16

Angle ∠ A = α = 38.9422441269° = 38°56'33″ = 0.68796738189 rad
Angle ∠ B = β = 38.9422441269° = 38°56'33″ = 0.68796738189 rad
Angle ∠ C = γ = 102.1155117462° = 102°6'54″ = 1.78222450158 rad

Height: ha = 8.87995510548
Height: hb = 8.87995510548
Height: hc = 5.65768542495

Median: ma = 10.87442815855
Median: mb = 10.87442815855
Median: mc = 5.65768542495

Inradius: r = 2.47548737342
Circumradius: R = 7.15994561595

Vertex coordinates: A[14; 0] B[0; 0] C[7; 5.65768542495]
Centroid: CG[7; 1.88656180832]
Coordinates of the circumscribed circle: U[7; -1.503260191]
Coordinates of the inscribed circle: I[7; 2.47548737342]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.0587558731° = 141°3'27″ = 0.68796738189 rad
∠ B' = β' = 141.0587558731° = 141°3'27″ = 0.68796738189 rad
∠ C' = γ' = 77.8854882538° = 77°53'6″ = 1.78222450158 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    