Medium
Which curve is not a polygon (open, non-closed figure among the given options)?
Explanation
Explanation
A polygon must be a fully closed figure made of straight line segments, with no gaps and no crossing lines. Rectangles, squares, and properly closed triangular figures all satisfy this condition. But a figure that remains open (its line segments don't meet to fully close the shape) cannot be called a polygon. So the correct answer is the open, non-closed curve, option (1).
PRO TIP
Re-check your working by substituting the answer back into the original question.