straal = 3 (slider from 0 to 5, step 0.1)
A = (0, 0)
c = Circle(A, straal)
B = Point(c)
C = Point(c)
e = CircleArc(A, C, B)
d = CircleArc(A, B, C)
f = Segment(B, C)
E = Point(d)
D = Point(e)
g = Segment(D, E)
F = Intersect(f, g)
h = Segment(A, F)
α = Angle(A, F, D)
β = Angle(D, F, C)
γ = Angle(D, F, B)