How would I make a circle in Minecraft with a diameter of 98 to 100 blocks?

I'm trying to make a circle with a diameter of 98-100 blocks, possibly larger, but I definitely can't go any smaller because of what I'm building. I'm not trying to make the full sphere, just a circle.

Any response will be greatly appreciated.
Thanks.

Added (1). Thank you very much for pointing that out? MysteryMan? I figured I would get a response like that after I entered the question. I realize you can't actually make circle and spheres. Still i would like to know the block dimensions to be able to make a circle-like creation.

NO CIRCLES IN MINECRAFT

You can just Google: "Voxel Sphere Generator" and it should come up
but I found this video helpful as well: