q. 7 from geometry question bank

[iv_stoyanov]

Is quadrilateral ABCD a rhombus?
1/ AC and BD and perpendicualr bisectors of each other
2/ AB=BC=CD=AD

Per answers correct answer is D) 1 and 2 alone are SUFF
explanation for sta 2: if a quadrilateral has AB=BC=CD=AD, by definition this is a rhombus.

As far as I know a quadrilateral with AB=BC=CD=AD could also be a square?!?

[RonPurewal]

Per answers correct answer is D) 1 and 2 alone are SUFF
explanation for sta 2: if a quadrilateral has AB=BC=CD=AD, by definition this is a rhombus.

As far as I know a quadrilateral with AB=BC=CD=AD could also be a square?!?

ya, but squares are rhombuses too. they're just very special rhombuses.

this is exactly like the way that squares are also rectangles.
for instance, if i tell you that the four angles of a quadrilateral are right angles, then you can say Yes to "is it a rectangle?" -- even though it might be a square, since squares are still rectangles.

--

btw, i don't really know why we're talking about rhombuses; the word "rhombus" definitely appears 0 times in og11 and og12, and i don't think i've seen it in gmat prep either.
i'll submit this question for review, thanks.