None.
None. Since the number of sides is odd, there can be no parallel sides.
Infinitely many. Every regular polygon with 2n sides has n pairs of parallel sides. Then there are irregular polygons which can have parallel sides. And there are also irregular shapes which have parallel sides.
Their are 4 pairs of parallel sides on an octagon. In fact, for any regular polygon with an even number of sides, there will be # of sides / 2 number of pairs of parallel lines.
There are infinitely many such shapes. A polygon with 4 or more sides can have two sides that are parallel and they need not be the same length.
5 pairs of parallel sides.
None.
None. Since the number of sides is odd, there can be no parallel sides.
Infinitely many. Every regular polygon with 2n sides has n pairs of parallel sides. Then there are irregular polygons which can have parallel sides. And there are also irregular shapes which have parallel sides.
A decagon has 10 sides. Any regular polygon with four or more sides will have pairs of sides that are parallel. A decagon will have 5 pairs of parallel sides.
None.
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A 3-sided polygon has 0 parallel sides. A 4-sided polygon can have 0, 2 or 4 parallel sides. A 5-sided polygon can have 0, 2, 3 or 4 parallel sides. In general, an n-sided polygon can have 0, 2, 3, ..., n-1, or n parallel sides where n>5. A polygon with n sides can have n pairs of parallel sides (if n is even) or (n-1)/2 pairs if n is odd AND greater than 3. But it need not have any.
None. (As there are an odd number of sides, each side is opposite a vertex and there are no parallel sides.)
A polygon with n sides can have n pairs of parallel sides (if n is even) or (n-1)/2 pairs if n is odd AND greater than 3. But it need not have any.
Their are 4 pairs of parallel sides on an octagon. In fact, for any regular polygon with an even number of sides, there will be # of sides / 2 number of pairs of parallel lines.
A decagon has 10 sides. Any regular polygon with four or more sides will have pairs of sides that are parallel. A decagon will have 5 pairs of parallel sides.