A \; = \; | \vec{ F } |.| \vec{ OO' } |.cos(φ)

A = (-1.731718356625751, 0.254299350496478)
B = (1.5525139949560398, 0.2730663925055168)
a = Line(A, B)
O = (-0.5944356108779995, 0.3256141101308255)
D = (1.0983515783373008, 1.3015002946008434)
b = Segment(O, D)
F = Point(b)
u = Vector(O, F)
c = OrthogonalLine(F, a)
d = OrthogonalLine(O, c)
O' = Intersect(c, d)
φ = Angle(O', O, D)
v = Vector(O, O')