GMATinsight wrote:

Is Quadrilateral ABCD a Rhombus?

1) Diagonals of ABCD intersect each other at 90 degrees

2) Diagonals of ABCD are equal in dimension

Source:

http://www.GMATInsight.comDiagonals of the Quadrilateral ABCD intersect each other at 90 degrees: Quadrilateral can be Rhombus or Kite. Hence, Statement-1 is insufficient.

Diagonals of the Quadrilateral ABCD are equal in dimension: Quadrilateral can be Square (note that Square is a Rhombus with each interior angle as 90 degrees) or Rectangle or a Trapezium with equal non-parallel sides. Hence, Statement-2 is insufficient.

Both statements together: Diagonals of Quadrilateral ABCD intersect each other at 90 degrees and are equal in dimension. The quadrilateral has to be a Square (which is a Rhombus with each interior angle as 90 degrees). Thus, both the statements combined give a definite answer. Hence, both the statements together are sufficient to answer the question.

Answer: C. However, OA says it's E. How? If not please modify the OA.

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