5
A regular pentagon has zero perpendicular sides. If it is irregular, it could have as many as 2 or 4 perpendicular sides.
2
None
It can have one or two.
A single side cannot be perpendicular on its own. Two sides are perpendicular if they intersect at a 90 degree angle. There are many polygons, both regular and irregular, that can have perpendicular sides.
None normally in a regular 5 sided pentagon but it is possible to construct an irregular pentagon with a pair of parallel sides.
A regular 5 sided pentagon has no perpendicular lines
There isn't really a good straight answer for that - if it's irregular, then it would completely depend on the hexagon...
count the corners! Penta=5, five sides=5 angles, five angles equal 5 intersections. Some of these may be perpendicular, but not necessarily.
A pentagon can have:none (regular or irregular pentagon)one, two or three right angles (irregular pentagon).
5
A pentagon has 5 sides