There's no such concept as "close" in mathematics. Or at least, you have to specify when you consider two numbers to be "close".
All we can say is that, since 3/4=0.75, the two numbers are

units apart. Is this small enough to consider them as "close"? Is this big enough to consider them not to be "close"?
You should clarify more what you mean so that a definitive answer can be given.