A = (2.48, 4.84)
B = (7.84, -3.12)
g = Line(A, B)
C = (1.28, 2.32)
b = OrthogonalLine(C, g)
D = Intersect(g, b)
α = 0.8203047484373349 rad (slider from 0 to 3.141592653589793, step 0.017453292519943295)
D' = Rotate(D, -1.0 * (α - 90.0 * °), C)
β = Angle(D', C, D)
c = Line(C, D')
E = Intersect(c, g)
d = Segment(C, E)
γ = Angle(C, E, B)