You learned in geometry that a quadrilateral with four congruent sides is a rhombus. Which of the following statements is not equivalent to the one above?
1) All quadrilaterals with four congruent sides are rhombuses.
2) If ABCD is a quadrilateral with four congruent sides, then ABCD is a rhombus.
3) For all quadrilaterals ABCD, if ABCD has four congruent sides, then ABCD is a rhombus.
4) Every quadrilateral that has four congruent sides is a rhombus.
5) All of the above are equivalent.
