lengte = 5 (slider from 0 to 8, step 0.1)
A = (-3, -2)
hoekbl = 1.0995574287564276 rad (slider from 0 to 119°, step °)
hoekro = 0.9250245035569946 rad (slider from 0° to hoekbl, step °)
D = Point(Circle[A, lengte])
f = Segment(A, D)
D' = Rotate(D, hoekbl, A)
g = Ray(A, D')
A' = Rotate(A, (-hoekro), D)
h = Ray(D, A')
E = Intersect(g, h)
i = Segment(A, E)
j = Segment(D, E)
α = Angle(D, A, E)
β = Angle(E, D, A)