A polygon is a plane figure that is bounded by three or more straight sides that meet in pairs. (This means that it has as many vertices as sides). It encloses one contiguous area.
A polygon
Like this
the polygon would be a square
A polygon is a plane figure that is closed with straight line segments.
it look like a fifty sided shape
polyhedron
a triangle.
It is a seven-sided polygon
Polygon
The Pentagon.
It is a quadrilateral.
Since there is no need for it to be a regular polygon, it will look like a closed loop.