A single side cannot be concave and so the question makes no sense.
A concave hexagon can have 6 perpendicular sides if you count the external angle of one. The angles would be 90, 90, 90, 90, 90, 270
A nonagon has nine sides: whether it is concave or convex is irrelevant.
It has parallel sides, but not perpendicular.
Mutually perpendicular, adjacent sides.Mutually perpendicular, adjacent sides.Mutually perpendicular, adjacent sides.Mutually perpendicular, adjacent sides.
Adjacent sides are perpendicular. Opposite sides are parallel.
shape no pairs of perpendicular sides
No sides perpendicular means no right angles. A rhombus is a quadrilateral with no right angles so no sides perpendicular.
The question contradicts itself. A dodecagon need not have any perpendicular sides.
Yes. All polygons with 4 or more sides can be concave. An arrowhead is an example of a concave quadrilateral. The back of an envelop (where the sides are folded and glued together) is a concave pentagon.
No. a equilateral triangle does not have perpendicular sides.
No. a equilateral triangle does not have perpendicular sides.
A rectangle always has perpendicular sides.