straal = 3 (slider from 0 to 5, step 0.1)
A = (0, 0)
c = Circle(A, straal)
B = Point(c)
C = Point(c)
f = Segment(B, C)
D = Point(f)
g = Segment(A, D)
h = Ray(A, D)
E = Intersect(c, h, 1)
i = Segment(D, E)
j = Segment(A, B)
k = Segment(A, C)
α = Angle(A, B, D)
β = Angle(B, D, A)
γ = Angle(A, C, D)