parallelogram
Parallelogram
A square is a regular polygon with two sets of parallel sides. A parallelogram is an irregular polygon with one set of parallel sides. A rhombus is an irregular polygon with two sets of parallel sides. A rectangle is an irregular polygon with two sets of parallel sides. *Note - a regular polygon is a shape in which all sides are equal in length and all angles are equal in measurement.
A regular decagon would have five sets or parallel lines.
A rectangle has 2 "SETS" of parallel lines. SO it has 4 parallel lines.Two pairs.
You can construct any polygon with more than 4 sides such that two sides are parallel. A quadrilateral in which two lines are parallel is called a trapezoid.
parallelogram
Since you described it as 2 sets of parallel sides, I'll assume you meant a 4 sided polygon(quadrilateral). This special case is called a rhombus.
When it has two sets of parallel lines
When it has two sets of parallel lines
A parallelogram.
Parallelogram
there are 2 sets of parallel lines in a square
A square has four sets of parallel lines.
Well a nonagon is a nine sided polygon. If you make the lines or sides parallel, then you will have a parallel figure. Or some parallel lines on a figure (polygon). If you choose to make your polygon (nonagon) have a pair of congruent sides, then your polygon will have some congruent sides. Therefore it really matters what your shape looks like. For example, a quadrilateral can be a square or a kite (or many others but I'm just using these) a kite might have no parallel lines and a square may have 2 sets of parallel lines. Do you get it? Does that answer your question? FYI: A nonagon is also known as a enneagon :)
When it has two sets of parallel lines
General term for a polygon with 4 sides is a quadrilateral. A parallelogram is the special case with two pairs of parallel sides.