Given that p represents "The shape is a rhombus", q represents "The diagonals are perpendicular", and r represents "The sides are congruent".
"if and only if" is represented using the biconditional logic operator (↔) and "and" is represented using the logical conjuction operator (∧).
Therefore, "The shape is a rhombus if and only if the diagonals are perpendicular and the sides are congruent” is represented by "p ↔ (q ∧ r)"