A perpendicular side is a right angle.A right angle is a
perfectly L on any corner.The shape has to have no straight lines
that meet.An example would be a triangle.

The question asks about four sides and 2 perpendicular sides. That makes 6 sides in all. So it is a hexagon with either only one right angle, or two sides that are mutually perpendicular.

The question does not make any sense. "Adjacent" means next to. A shape cannot be next to itself, and if it is next to another shape, then you have two shapes. "perpendicular" means at right angles (or 90 degrees) to. Again, a shape cannot be perpendicular to itself.