How would you define a polygon?

• A. Line.
• B. Polygon.
• C. Point.
• D. Curve.

Answer: (B)

A polygon is a closed figure in the plane formed by straight line segments that connect end to end, returning to the starting point. It must have at least three sides, and the corners where the segments meet are called vertices. Because all sides are straight and the boundary is closed, a polygon encloses a two-dimensional region. This distinguishes it from other shapes: a line extends forever without closing, a point has no size or extent, and a curve may be curved and not necessarily composed only of straight segments or form a closed boundary. So the defining feature is a closed chain of straight segments forming a polygonal boundary.