it is a square because a square has four side and four right angels
A quadrilateral is a closed plane figure with four straight sides.
It is a polygon that is a closed plane figure with 3 or more straight lines.
A polygon
If they are straight sides, then a polygon. Otherwise, simply "a closed plane figure with 3 or more sides".
Polygon
hendecagon
A polygon
Yes
A plane figure with 7 straight sides
A polygon is a plane figure with 3 or more straight sides and angles. A plane figure is a flat enclosed figure made of straight lines, curved lines, or both.
yes
A dodecagon is a plane (2-dimensional) figure which is bounded by 12 straight lines.