A parallelogram.
square
Rectangle
The quadrilateral described is a rectangle. In a rectangle, opposite sides are equal and parallel, and all four angles are right angles. This definition meets the criteria of having one pair of opposite sides that are equal and parallel, along with the presence of right angles.
The shape you are describing is a rhombus. A rhombus has all four sides of equal length, opposite sides that are parallel, and opposite angles that are equal. When the diagonals of a rhombus are drawn, they intersect at right angles.
Rhombus
Quadrilaterals
rectangles squares
A rhombus has 4 sides of equal length, opposing parallel sides, and no right angles
A rhombus
A rhombus
a parallogram
It is a square or a rectangle