5th Grade · Geometry
Polygon
5.G.B.3
Definition
A closed two-dimensional figure with three or more straight sides.
Examples
- A triangle (3 sides), quadrilateral (4 sides), pentagon (5 sides), and hexagon (6 sides) are all polygons.
- A circle is not a polygon because it has no straight sides.
Key rule
A shape with curved sides or that isn't closed is not a polygon.
Memory hook
Closed shape, straight sides only.