A = (3.803499533703866, 5.683289617336226)
B = (-1.7019102052555781, -4.231792970789763)
a = Segment(A, B)
C_1 = (3.7233236637190195, -7.492278350173511)
b = Line(A, C_1)
C = Mirror(B, b)
đa giác1, b', a_1, b_1 = Polygon(A, B, C)
H = Intersect(b, a_1)
c = Segment(A, H)
α = Angle(C, H, A)