Only a parallelogram. You can technically say a square does as well, although all sides are congruent in a square (compared to the parallelogram with two sets of opposite sides congruent).
A square's opposite sides are parallel and all the sides are congruent.
Trapezoid.
There is no specific name for such an irregular quadrilateral.
No, you need both pairs of opposite sides to be congruent (i.e. the same size) to be a parallelogram.
A square
The Opposite Sides Parallel and Congruent Theorem states that if a quadrilateral has a pair of opposite sides that are parallel and congruent, then the quadrilateral is a parallelogram.
A quadrilateral with both pairs of opposite sides congruent is a parallelogram.
A parallelogram has two pairs of congruent sides, and the opposite sides are congruent.
No. The congruent sides need not be parallel.
Then, the opposite sides are congruent.
parellelagram
always
A square's opposite sides are parallel and all the sides are congruent.
If a quadrilateral has two pairs of opposite congruent sides, then the quadrilateral is a parallelogram.
Parallelograms, rhombuses, squares, and rectangles are the quadrilaterals that have opposite congruent sides.
Diamond
Trapezoid.