g⊥h

A = (1.5491574074074073, 6.147873015873018)
B = (11.06580740740741, 0.34569894179894284)
g = Line(A, B)
C = (9.33057777777778, 9.699671164021169)
h = OrthogonalLine(C, g)
D = Intersect(g, h)
α = Angle(g, h)