5. Illustrate, if possible, each one of the following with a rough diagram:
(a) A closed curve that is not a polygon.
(b) An open curve made up entirely of line segments.
(c) A polygon with two sides.
(a) A closed curve that is not a polygon is possible.
e.g an ellipse or a circle
(b) An open curve made up entirely of line segments
(c) A polygon with two sides is not possible since by definition polygons are closed figures which require at least three line segments to be made.