Actually, we prefer if you post separate questions on separate threads.
Basically, this problem amounts to finding the angle between two vectors - one that represents your original tower and another one that represents the tower that is now tilted.
So, since the original tower was vertical to the original ground, it is parallel to the vector (assuming the z component is 'up' and the xy plane forms the original ground).
Now, use your 3 points on your 'new' ground, form the 2 vectors and take its cross product to get soem vector . This will yield a vector perpendicular to your tilted ground and so, it is parallel to your tilted tower.
So the angle between and should also be the angle between the original and tilted tower.
Use this relationship to find your angle: