square
A square's opposite sides are parallel and all the sides are congruent.
Trapezoid.
There is no specific name for such an irregular quadrilateral.
A square
always
It is a rectangle.
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.
square
parellelagram
A square, always, a rhombus, always, a parallelogram, always, and rectangles, 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.