My swf size doesn't match up with ppt slide size

Greetings,

A friend is wanting to run a brief Flash animation in his ppt. I’ve
made the animation to match his ppt document size which is 10" wide by
7.5" height. In the document settings I’ve set the Flash stage size to
720 pixels wide (10") by 540 pixles (7.5") height. Yet, when I publish
the swf, it seems smaller than the ppt slide. I’ve sent the swf to my
friend and he says it’s not filling the document size. Does Microsoft
and Adobe have different measurements for pixels and inches? Actually,
I’m sure it’s me doing something wrong that is common knowledge to
most Flash users, but I can’t seem to find the answer anywhere. Any
help would be greatly appreciated.

Thanks,
bfg