# 5 6 6 triangle

### Acute isosceles triangle.

Sides: a = 5   b = 6   c = 6

Area: T = 13.63658901433
Perimeter: p = 17
Semiperimeter: s = 8.5

Angle ∠ A = α = 49.24986367043° = 49°14'55″ = 0.86595508626 rad
Angle ∠ B = β = 65.37656816478° = 65°22'32″ = 1.14110208955 rad
Angle ∠ C = γ = 65.37656816478° = 65°22'32″ = 1.14110208955 rad

Height: ha = 5.45443560573
Height: hb = 4.54552967144
Height: hc = 4.54552967144

Median: ma = 5.45443560573
Median: mb = 4.63768092477
Median: mc = 4.63768092477

Inradius: r = 1.60442223698
Circumradius: R = 3.33001145893

Vertex coordinates: A[6; 0] B[0; 0] C[2.08333333333; 4.54552967144]
Centroid: CG[2.69444444444; 1.51550989048]
Coordinates of the circumscribed circle: U[3; 1.37550477455]
Coordinates of the inscribed circle: I[2.5; 1.60442223698]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.7511363296° = 130°45'5″ = 0.86595508626 rad
∠ B' = β' = 114.6244318352° = 114°37'28″ = 1.14110208955 rad
∠ C' = γ' = 114.6244318352° = 114°37'28″ = 1.14110208955 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    