In space, as invisible, nonmaterial geometric figures. A circle is the set of points in one plane equidistant from one point. Do you want to argue that the entire course of geometry is a crock of shit?
Where would one find a circle, in the universe? Circles are just approximations. In fact the whole of geometry is an approximation of reality, because Euclid's parallel axiom (that two parallel lines never meet) is actually wrong in our reality.

If you say that a circle, ie. x2 + y2 = r2, is real, then really, by extension, every other equation is real.

1/2x5 + x4 + x2 + 9x1/2 + x + e = 0

dy/dx + y.tanx = x^-pi

(2 + 9i)x^4 + (1/2 - 5i)x^3 = 11i

[2 x]^2 + I = O
[4 2]

Where are these things real? Why are they real? None of them will approximate perfectly to reality. Most of them will not approximate to reality at all. There will be an infinitude of infinities, each different equation and type of number becoming steadily more and more obscure until they have no meaning at all.

The idea that numbers are 'in space' demands an explanation, too. What exactly do you mean by that? By what distances are these numbers separated?