It would be almost indistinguishable from a circle.
A polygon
it look like a fifty sided shape
Like this
see related link below to see the 20 sided polygon
polyhedron
a triangle.
It is a seven-sided polygon
The Pentagon.
It is a quadrilateral.
It looks like a circle
A nonagon is a nine-sided polygon.
Join up the hour-markers on a clock face and you will have a dodecagon - a 12 sided polygon.