Explanation
In this figure, we appear have three squares and a right
triangle, although the question itself prior to the data statements only
identifies B as a square. We want the area of triangle D, so we will need a
valid base-height pair. But since D is a right triangle, we can find the length
of any third side given the other two sides, with the Pythagorean Theorem.
Therefore, any two lengths along the triangle will be sufficient. And since the
area of square B is 4, we have a length of 2 on that side. We need only one
more length of the triangle for sufficiency.
Statement (1) tells us another side of the triangle (it's 3), so it is sufficient.
Statement (2) also tells us another side of the triangle (it's
, so it is sufficient. The correct answer is (D).
By the way, if this figure looks familiar to you from your
early education, you may have seen it as part of a proof of the Pythagorean
Theorem. Keep in mind, however, that trigonometry (that is, sines,
cosines, tangents, and so on) are not tested on the GMAT. Of special note on
the GMAT is that the distance formula in the coordinate plane is essentially an
application of the Pythagorean Theorem, and that fact will come up on some
questions.
Again, the correct answer is (D).
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