Angulo Inscrito en una Semecircunferencia

A = (0, -2)
B = (9.080000000000002, -1.96)
c = Semicircle(A, B)
a = Segment(A, B)
C = Midpoint(A, B)
α = 1.1693705988362009 rad (slider from 0 to 3.141592653589793, step 0.017453292519943295)
D = Rotate(B, α, C)
β = Angle(B, C, D)
poly1, a_1, b, d = Polygon(B, D, A)
γ = Angle(A, D, B)
δ = Angle(B, A, D)
ε = Angle(D, B, A)