A parallelogram with perpendicular sides is called a rectangle.
By definition, a parallelogram two separate pairs has parallel sides. The only type of parallelogram that has perpendicular sides is a rectangle. All others have non-perpendicular sides.
No. A parallelogram has two parallel sides.
No. Not necessarily.
A parallelogram doesn't necessarily have any perpendicular sides, but it can. If it has one single 90-degree angle, then it has four of them, and it's a rectangle or square. A parallelogram without perpendicular sides is a rhomboid or rhombus.
The question contradicts itself. A dodecagon need not have any perpendicular sides.
Not normally but as a rectangle it has perpendicular sides that meet at right angles
Only in the special case when the parallelogram is a rectangle