A polygon
A polygon.
A polygon would fit the given description.
If none of the sides ever cross each other, there cannot be a closed plane figure.
polygon
Polygon
US DefinitionA trapezoid is a closed plane figure consisting of four line segments/sides; two of these line segments are parallel (but not equal in length) and two are nonparallel.(in the UK, this is called a trapezium)British DefinitionA trapezoid is a closed plane figure consisting of four line segments/sides; NONE of these line segments are parallel to any of the other line segments of the quadrilateral.(in the US this is just a quadrilateral)*(see the related links for images of trapezoids)
a polygon
All sides are connected with no open gaps, sides do not intersect or cross over each other.
A polygon is a plane figure which comprises one area bounded by three or more straight line segments. A general plane figure can have curved boundaries or sides that cross each other.
Perpendicular line segments are line segments that cross with each other and form angles of 90 degrees.
A closed shape that is not a polygon made entirely of segments is a circle. Unlike polygons, which are composed of straight line segments, a circle is defined as the set of all points equidistant from a central point, and its boundary is smooth and curved. Other examples include ellipses and certain types of curves, such as ovals or closed curves like a figure-eight. These shapes do not have the straight edges characteristic of polygons.
a quadrilateral and other polygons