There are also other ways that you may find better suited to some situations.
You could MOVE things with the end-of-displacement picked using PERpendicular Object Snap, even if the end location is not actually on the thing you Move PERpendicular to. For example, to align the left side of the red box here with the yellow Line, the left half of the image resulting in the right half:

[Note that the "dragged" position of the red square at lower left is down at the cursor, but the green PERpendicular icon shows where it's going to end up.]
You can use >Coordinate Filters< to pull one coordinate from one source and the other(s) from another source [or two from one source and the other from another].
For middle-type choices, you can use Mid-of-2-Points [M2P/MTP] Object Snap.
Etc. The right choice depends a lot on the kind(s) of objects involved, and sometimes on their configuration.
Kent Cooper, AIA