No perfect circles possible? (No, really. Seriously)

[Maschinenbauer]

So, I tried to design a perfect circle. All the ones iI´ve seen so far always seemed a bit off. When I tried it and checked it I found that my suspicions were right. The curve tool draws eggs.

I made a small example in a perfect 60x60u square:

Here´s the problem in a bigger square:

I need help! Either with my ocd or with the broken tool

Thx in advance!

 

[Londo Milar]

I think i already helped you....
Make 45 Degree "Helpstreet" with a length of 400 Units and than use the freehandtool in a 90 degree angle.
Don't no why but the curvetool isn't good for curves bigger than 50 units.