2π/5

2π /5

2π /5

2π /5

2π /5

A = Intersect(xAxis, yAxis)
c = Circle(A, 5)
d = Circle(A, 4.992678018677139)
B = Point(d)
B' = Rotate(B, 72°, A)
α = Angle(B, A, B')
B'' = Rotate(B', 72°, A)
β = Angle(B', A, B'')
B''' = Rotate(B'', 72°, A)
γ = Angle(B'', A, B''')
C = Rotate(B''', 72°, A)
δ = Angle(B''', A, C)
C' = Rotate(C, 72°, A)
ε = Angle(C, A, C')
u = Vector(A, B)
v = Vector(A, B')
w = Vector(A, C)
a = Vector(A, B''')
b = Vector(A, B'')