Which of the following statements is not always true?

A parallelogram always has two pairs of parallel opposite sides, equal lengths for each pair of opposite sides, and diagonals that bisect each other. Its diagonals are not always congruent: they are congruent in special cases such as rectangles, but not in every parallelogram. Therefore, the statement that is not always true is “In a parallelogram, the diagonals are congruent.”

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