2D Vector bullshit

I've got 2 points (ie. X,Y vectors), and I need to find out the angle (degrees°) between them, so I can move an object which is at one of the points towards the other point.

How do I calculate the degrees plz???

BTW if you dont know what dot and length are:

dot(X, Y) = X[1]*Y[1] + X[2]*Y[2]
length(X) = sqrt(X[1]*X[1] + X[2]*X[2])

Good day.