four (4)
In a regular octagon, there can be multiple sets of parallel lines. Specifically, each pair of opposite sides of the octagon is parallel to each other. Since an octagon has 8 sides, there are 4 pairs of parallel lines, resulting in a total of 4 distinct sets of parallel lines.
A parallogram has two pairs of parallel sides. A trapezoid has one pair of parallel sides. A regular octagon has four pairs of parallel sides. An irregular octagon may have from 3 pair to no pair of parallel sides.
2 pairs of parallel lines
1 pair of parallel line
An octagon can have up to four pairs of parallel sides, but it need not have any.
A rhombus has 2 pairs of parallel lines.
It has a pair of opposite parallel lines of different lengths
A trapezoid has one pair of parallel sides. They are opposite parallel lines of different lengths.
Two.
2
Zero
1 pair of parallel lines