A parallelogram is a specific type of quadrilateral where both pairs of opposite sides are parallel. For a parallelogram to be classified specifically as a square, it must satisfy certain conditions. The statement that describes a parallelogram that must be a square is: “All sides are equal in length and all angles are 90 degrees.” This means that not only do the opposite sides need to be equal and parallel (as in all parallelograms), but the adjacent sides must also be the same length, and each angle must measure exactly 90 degrees.
In essence, while every square is a parallelogram, not all parallelograms are squares. A square possesses additional properties that make it unique: the equal length of sides and the presence of right angles. Only when these conditions are fully met can we confirm that the parallelogram is indeed a square.