What is the name of a ten billion sided polygon?

Answer 1

While there is no prevalent name for such a polygon, due to its insurmountable number of sides (to the unaided eye, it would be indistinguishable from a circle; such a polygon would still be indistinguishable from a circle if it were the same size as the sun, and would need to be several lightyears in diameter before its angles would be discernible and its perimeter of significant distance from that of a corresponding circle). A term can be inferred from the metric naming system: 1 billion is represented by 'giga', ten by 'deca', so an approximate name would be 'decagigagon'.