Spacer Lift Question..

Ok just got a quick question, and yes I searched first but couldn't figure out how to word it to get my answer. Before someone goes on a rampage, I'm not considering buying a spacer lift for my truck (actually going 885's, billy's, uca's, etc..). Just got into a conversation with some buddies, and I'm sorry for the dumb question, but I just don't understand. I was wondering if someone could explain the concept behind a spacer lift? What I mean by this is, how does a 3/4" spacer provide 1.5" of lift, 1" spacer provide 2" of lift, and so on?

I'm sorry for the newb question, but nobody I know can answer this question for me so I figured you guys could. Thanks for any help.

 

its do to the position of the shock. so when extending the shock the wheel will move further since it is further from the pivot point

fulcrum laws