Nope, you cannot. Certainly not with the information provided.
100 sqft? You realize that's only a 10x10 foot chunk of real estate, right?
You probably could cover with that, but you are gonna be "challenged" to get those three channels (1, 6, 11 if you're talking 802.11g) assigned on your 400 or so APs.
It doesn't matter, even if you meant 1000 sqft or 10,000 sqft.
You don't mention if this is wide-open territory, warehouse, offices, how many floors, construction materials, environment, potential noise sources, potential band / channel conflicts, ceiling height, floor covering, number of windows, type of client, blah blah blah blah .....
Unfortunately, you can make *no* assumptions with wireless. You can't see RF, so you don't know what's "really" going on in your space.
Even you have "hyper coverage" (like 100sqft per AP), there are no guarantees; it's always a crap-shoot.
Your ONLY way to be sure of your coverage is to do a comprehensive site survey, and even then there's always a few gotchas waiting in the wings.
Make no assumptions, especially if there's reputation or money on the line. Assumptions will cost you big time in both when things get ugly.
Good Luck
Scott
