AB=

AC=

BC=

AB/BC=

AC/BC=

AC/AB=

B = (-2.04, -0.8)
α = 0.6981317007977318 rad (slider from 0 to 90*°, step 0.017453292519943295)
C_2 = (3.5, 0.4)
C_1 = Rotate(C_2, α, B)
β = Angle(C_2, B, C_1)
a_1 = Segment(B, C_2)
b = Ray(B, C_1)
A = Point(b)
a = Segment(B, A)
e_1 = Ray(B, C_2)
C = Point(a_1)
d = Segment(A, C)
e = Segment(B, C)