yes
Yes.
yes
All regular polygons do.
almost all even number of sided polygons, regular has to be
yes
no
All regular ones do.
Yes.
yes
All regular polygons do.
Regular polygons.
almost all even number of sided polygons, regular has to be
All of them have rotational symmetry because all the sides and angles have to be the same in order for the polygon to be a regular polygon
There would be too many to name. All regular polygons have a line of symmetry, but there are still polygons that don't.
yes
Lines of symmetry in polygons are not necessarily diagonals. A line of symmetry divides a shape into two identical halves, while a diagonal connects non-adjacent vertices of a polygon. In some cases, a diagonal can serve as a line of symmetry, but this is not true for all polygons. Therefore, while there can be overlap, the two concepts are distinct and not synonymous.