r 

r = 2 (slider from 1 to 4, step 1)
A = (6.622883244796336, -2.604036116198296)
a_1: abs(r)
B = Point(Circle[A, abs(r)])
r_2 = Segment(A, B)
α = 2.0943951023931953 rad (slider from 3.75*° to 120*°, step 0.25*°)
B' = Rotate(B, α, A)
β = Angle(B, A, B')
c = Circle(A, B)
b = Segment(A, B')
g = Segment(B', B)
B'' = Rotate(B', α, A)
γ = Angle(B', A, B'')
e = Segment(A, B'')
f = Segment(B'', B')
B''' = Rotate(B'', α, A)
δ = Angle(B'', A, B''')
g_1 = Segment(A, B''')
h_1 = Segment(B''', B'')
C = Midpoint(B, B')
h = Segment(C, A)
Vieleck1, b_1, b', a = Polygon(B', A, B)
ε = Angle(B', C, A)