A = (-2.78, 0.56)
B = Point(Circle[A, 7.6])
c = Segment(A, B)
d = Circle(B, 5.8)
e = Circle(A, 11.3)
C, D = Intersect(d, e)
Vieleck1, d_1, a, b = Polygon(A, B, D)
α = Angle(B, A, D)