A_1 = (0.35599057493546366, 13.056904028102569)
B_1 = (0.42713329690201735, -4.693205102552554)
a = Line(A_1, B_1)
α = 0.4014257279586958 rad (slider from 0 to 3.141592653589793, step 0.017453292519943295)
A = (-5.121999016489163, 10.993765091072515)
B = (-9.283848251532564, 6.725201773079299)
C = (-3.094431440442385, 0.46464224002258203)
đa giác1, e, c, d = Polygon(A, B, C)
C'_1 = Mirror(A, a)
B' = Mirror(B, a)
C' = Mirror(C, a)
đa giác1', e', c', d' = Polygon(C'_1, B', C')
A' = Rotate(C'_1, α, C'_1)
B'' = Rotate(B', α, C'_1)
C'' = Rotate(C', α, C'_1)
đa giác1'', e'', c'', d'' = Polygon(A', B'', C'')
β = Angle(C', A', C'')
γ = Angle(B', A', B'')