Ray/Plane Intersection

Ray is defined by R(t) = Ro + Rd*t where t > 0
Ro = Origin of ray at (xo, yo, zo)
Rd = Direction of ray [xd, yd, zd] unit vector

Plane is defined by [A, B, C, D]
Ax + By + Cz + D = 0 for a point in the plane
A2 + B2 + C2 = 1
Normal Vector, Pn = [A, B, C]