On a quick estimate, I would think 18, 9 for each interior side and another 9 for each interior angle. * * * * * A nonagon has only 9 lines so the above answer is nonsense. With 9 lines you can have at most 4 pairs of parallel lines (and one not parallel to any). Or you could have a concave nonagon with 1 pair, 1 triplet and 1 quartet of parallel lines, or some other combination.
A pentagon has no parallel lines.
Here are three shapes that have two pairs of parallel lines: square parallelogram rectangle There are many polygons with at least two pairs of parallel lines. hexagon (has 3 pairs of parallel lines) octagon (has 4 pairs) decagon (has 5 pairs)
0 pairs
A regular pentagon has no parallel lines.
In a regular nonagon no two sides are parallel.
Up to four.
On a quick estimate, I would think 18, 9 for each interior side and another 9 for each interior angle. * * * * * A nonagon has only 9 lines so the above answer is nonsense. With 9 lines you can have at most 4 pairs of parallel lines (and one not parallel to any). Or you could have a concave nonagon with 1 pair, 1 triplet and 1 quartet of parallel lines, or some other combination.
A diamond has two pairs of parallel lines.
A rhombus has 2 pairs of parallel lines.
A regular dodecagon has six pairs of parallel lines.
it has 2 pairs of parallel lines
it has too parallel lines!
A pentagon has no parallel lines.
A regular octagon has four pairs of parallel lines.
A square has 2 pairs of equal opposite parallel lines
A parallelogram has 2 pairs of parallel lines