Question

For a quadrilateral to be a square, the diagonals must beCongruent and perpendicularCongruent PerpendicularParallel

Answer 1

Recall that:

1) A quadrilateral is rectangle if it has congruent diagonals.

2) A quadrilateral is rhombus if it has perpendicular diagonals.

Also, recall that a square is a rectangle that is also a rhombus, therefore its diagonals must be congruent and perpendicular.

Answer: Congruent and perpendicular.