Assertion: polyhedron's polygon | /r/HasProperty | flat
Facets:
Source sentences:
text: Polygons are flat, two-dimensional figures (planes) bounded by straight sides.
text: Each face is a polygon (a flat shape with straight sides).
text: Polygons are flat figures made with a series of connecting line segments that form a closed shape.
text: A polygon is a flat or “planar” shape created with a series of connecting line segments: a triangle, for example, is a polygon.