Does that average american know that 3 buildings were destroyed on 9/11?

Very, very doubtful.

But since a dear friend of mine was actually walking into work that morning and only minutes from her office in WTC #7 when the attacks occurred, I've always been well aware of the fact that it was also destroyed.

http://en.wikipedia.org/wiki/7_World_Trade_Center

 

no.

they're too dumb and voted for Bush...