How to find out if I am related to this person?

[wendy c]

A simplistic way to explain being related to someone is if you share an grandfather (ancestor). So.. to know if you are related, what you have to have is both YOUR ancestors and HIS ancestors. In general, genealogy sites avoid posting personal info about a live person. I can (by choice) post that my ancestor is Edw. Wade, at the same time that I am not providing personal data about ME like my name/parents, so forth. Many celebrities avoid this a lot, to avoid being stalked or harrassed. You are entitled to know your ancestors, but not "entitled" to his..UNLESS it has been posted by someone's choice. I have seen family info for some persons on wikipedia, not that I agree with it.
Another "connection" could be that a distant cousin married this person. That does not involve your direct ancestor or his, but is a type of relationship. That includes much more extensive data/ research, beyond direct ancestors.
The short version is that LIVING persons information/ ancestry is generally not online, and should not be. You MIGHT find it..but not just the easy way by putting your name into some search box.
edit
actually, I HAVE located such info, because a famous person's ancestry did wind up online.. Alanis Morrissette does in fact SHARE an ancestor with my daughter's. I suspected it by the name, but until someone identified her line, I had no way to be sure.