From a CAT test from Manhattangmat; is this a parallelogram?

[val]

I´m confused in here, I have the following question for which my answer was E (the correct answer is A) because using both statements it could be any of two things; a parallelogram or a square. How do you know from the info provided that is not a square and that it is in fact a parallelogram?

In the quadrilateral PQRS, side PS is parallel to side QR. Is PQRS a parallelogram?

(1) PS = QR

(2) PQ = RS

[Ben Ku]

A math problem from our CAT practice tests should go in the MGMAT CAT Math folder.

Also, this question has been addressed previously here:
http://www.manhattangmat.com/forums/in-the-quadrilateral-pqrs-side-ps-is-parallel-to-side-qr-t936.html?hilit=quadrilateral%20PQRS

Hope that helps.