SAT Math Help Please? I suck at 3D visualization?

Test Preparation SAT Preparation
1

<p><a href=“http://i252.■■■■■■■■■■■■■■■/albums/hh17/xxEliza321xx/math.jpg[/url]”>http://i252.■■■■■■■■■■■■■■■/albums/hh17/xxEliza321xx/math.jpg&lt;/a&gt;&lt;/p&gt;

<p>The choices:</p>

<p>A) 1
B) 2
C) 3
D) 4
E) 5</p>

<p>Can someone explain to me why C is right? Again, I stink at 3D visualization :(</p>

2

<p>I believe the answer is D, not C. There are 4 vertices on the top of the cube. Each of these vertices is the endpoint of one “long diagonal.”</p>

3

<p>This is from Dr. Chung’s, which said the answer is C, but with no explanation.</p>

4

<p>Clearly it’s an error. The question itself alo has a typo. It should say “XY is a diagonal,” and NOT “XY is the digonal.”</p>

5

<p>There are four different diagonals that go through the center of the cube. You can create a 3D model using cardboard and toothpicks.</p>

<p>So either Dr. Chung made a mistake or he was trying to ask how many OTHER diagonals have the same length. But that is not how the question is worded. So I think that this would be an error in the book.</p>

6

<p>3 is correct: (Different)</p>

7

<p>If Dr. Chung is asking how many “different” diagonals there are, then there are 4 different diagonals in the cube.</p>

<p>If he is asking how many other diagonals there are (in other words, not including segment XY), then there are 3 other diagonals in the cube.</p>

<p>In my opinion, the question is poorly worded and obviously poorly explained by the author.</p>

8

<p>Whether you thought the answer was 3 or 4, there is nothing wrong with your 3d visualization. They just did not make clear whether they meant for you to count XY in the total. From their answer, we can reverse-engineer it to figure out that they did not mean for you to count XY, BUT THEY DID NOT SAY THAT! I think they mis-used the word “different” as in “how many different” when they should have said “other”. (Or maybe they felt they had to say “different” so you would not count XY and YX as separate diagonals. Not sure who would do that…)</p>

<p>And (1 minute later) I agree with knowthestuff</p>

9

<p>Hmmm…I think XY is the same length as XY, and it’s different from the other 3. So I would count it based on the wording of the question. But what do I know? Lol</p>

10

<p>Lol…I didn’t have ANY clue on how to go about this question…</p>

11

<p>Eliza, surely you have some cardboard around. Perhaps you have an old manila folder or some old index cards. Find some toothpicks, plastic straws, or anything else that has the shape of a rod.</p>

<p>Cut the cardboard into 5 squares of the same size. Tape the squares together so that you form a cube with an open top. To create your diagonal, lay the toothpick or straw from a corner at the top to the farthest corner at the bottom. Repeat this for the three remaining top corners. You will be able to see the four diagonals.</p>

12

<p>Broken record:</p>

<p>The only thing worse than using any of those error-laden synthetic tests is wasting time deciphering what the so-called author meant, or where his mistakes are.</p>

<p>Actually, there IS something worse, namely learning and remembering a lesson that is absolutely wrong. </p>

<p>This could be Exhibit 21,022 for the case “Why nobody should use non-official tests!”</p>

13

<p>^LOOOOOOOOL</p>

<p>Exhibit 21,022(I am impressed because you are counting them all)</p>

14

<p>That’s just this week. </p>

<p>Sent from my Droid using CC App</p>

15

<p>Well, it’s 3 if XY isn’t counted, and 4 if XY is counted.</p>

<p>The question doesn’t elaborate on it.</p>

16

<p>What is this ‘‘exhibit’’ stuff?</p>

17

<p>It’s a law/courtroom conceptual metaphor :). </p>

<p>“Exhibit” - the faulty questions that attempt to emulate real SAT questions</p>

<p>“Prosecutor” - Xiggi, et. al.</p>

<p>“Defender” - _______, et. al. </p>

<p>–</p>

<p>We use conceptual metaphors all the time. Time is often referred to in financial terms … </p>

<p>“Time is money.”</p>

<p>“You are wasting my time.” </p>

<p>“My car breakdown cost me an hour.”</p>

<p>“You need to budget your time wisely.”</p>

18

<p>Oh okay :)</p>