Fusion Tables, like all Google Maps stuff, works in WGS84. This is a specific projection for geographic data. Data that originates in another projection will need to be converted to WGS84 in order to show up properly on the map, and the conversion is more involved than just the number format. Each projection is a mathematical model of the surface of the Earth, and converting between them involves mathematical steps. I know some types of software can do this for you...

Hope that helps get you on the right course!

-Rebecca