MikeScarn wrote:
EMPOWERgmatRichC wrote:
Hi ZLukeZ,
In the prompt, we're told that X and Y are the two "legs" of the right triangle and that the PERIMETER = 4X
IF.....
the legs are X=3 and Y=4, then the perimeter is 4(3) = 12.
A 3/4/5 triangle has a perimeter of 3+4+5 = 12, so this "matches" what we were told.
IF....
the legs are X=4 and Y=3, then the perimeter is 4(4) = 16
This does NOT match the perimeter of a 3/4/5 triangle, so X CANNOT be 4.
GMAT assassins aren't born, they're made,
Rich
Why are you assuming it's a 3/4/5 triangle right off the bat? Could be a 45, 45, 90? I understand it works if we make it a 3,4,5 and make x=3 and y=4, but how do we know that's the only possible solution?
CC:
BunuelHi MikeScarn,
You ask some really good questions. To answer them, you have to remember a few things:
1) This is the GMAT, not a general "math test." The GMAT is built around patterns and is predictable (NOTHING in a question is there by chance - the wording is always really specific, the concepts tested are really specific and even the answer choices are specific), so you can use the patterns used by the question-writers to your advantage.
2) The answer choices can often provide a clue as to how to approach the question. Here, they help to define what is NOT possible. If we were dealing with a 45/45/90 triangle, then the ratio of the legs would be 1:1. That's clearly not an option here, so the triangle cannot be a 45/45/90.
GMAT assassins aren't born, they're made,
Rich
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