how many sides must a polygon have
A polygon must have at least 3 sides.
To determine how many sides a polygon must have, we need to understand the definition of a polygon.
A polygon is a closed two-dimensional shape made up of straight line segments called sides. Each side connects two vertices (corners) of the polygon.
In order to form a closed shape, a polygon needs a minimum of 3 sides. If a shape has fewer than 3 sides, it cannot form a closed shape and therefore cannot be considered a polygon.
So, to answer the question, a polygon must have at least 3 sides.