# 2 2 2 triangle

### Equilateral triangle.

Sides: a = 2   b = 2   c = 2

Area: T = 1.73220508076
Perimeter: p = 6
Semiperimeter: s = 3

Angle ∠ A = α = 60° = 1.04771975512 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 60° = 1.04771975512 rad

Height: ha = 1.73220508076
Height: hb = 1.73220508076
Height: hc = 1.73220508076

Median: ma = 1.73220508076
Median: mb = 1.73220508076
Median: mc = 1.73220508076

Inradius: r = 0.57773502692
Circumradius: R = 1.15547005384

Vertex coordinates: A[2; 0] B[0; 0] C[1; 1.73220508076]
Centroid: CG[1; 0.57773502692]
Coordinates of the circumscribed circle: U[1; 0.57773502692]
Coordinates of the inscribed circle: I[1; 0.57773502692]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 120° = 1.04771975512 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 120° = 1.04771975512 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    