Why didn't I get this SAT Math question right? Help?

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<p>What’s wrong with this picture?</p>

<p><a href=“http://i252.■■■■■■■■■■■■■■■/albums/hh17/xxEliza321xx/Photoon2012-08-29at1508.jpg[/url]”>http://i252.■■■■■■■■■■■■■■■/albums/hh17/xxEliza321xx/Photoon2012-08-29at1508.jpg&lt;/a&gt;&lt;/p&gt;

<p>I’m talking about question 15, the one with the triangles. The answer is supposed to be 1/2 or .5. So what’s wrong with what I did?</p>

2

<p>This is a ratio question. You assigned wrong values. First start with assigning the values. </p>

<p>QS/QV=1/3, from the figure you see that QS is a part of QV. QS is 1, then SV is 2.
PT/PR=3/4, again you see that PT is a part of PR. PT is 3, then TR is 1(4-3). </p>

<p>Now find the areas of the triangles. The area of PST is 2x3/2=3. The area of PQR is 3x4/2=6. </p>

<p>The value of the fraction is 3/6.</p>

3

<p>Your answer was .5625, close to 3/6 which is one half. I can’t tell what working you did but I can see that you labeled QS 3 and SV 9, which is where you made a mistake. If you had to use those proportions, QS would be 3 and SV would be 6 because it’s QS/QV not QS/SV, in which case you would use 3 and 9. Since it’s QS/QV, QV has to be QS+SV which has to equal 3 times QS. Again, I can’t tell if this is what you did but if it is, then that’s your error!</p>

4

<p>“So what’s wrong with what I did?”</p>

<p>Used a 9 instead of 6.</p>

<p>The wrong entry in your work is 21(9) = 189 … It should have been 21(6) or 126. And 28(12) should have been 28(9) or 252. </p>

<p>126/252 = 1/2. </p>

<p>PS This shows your errors, but smaller entered values would have worked better.</p>

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<p>thanks guys!</p>

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<p>Area = bh/2 where b,h are the base and height. Replacing b with 2b/3 and h with 3h/4, you obtain</p>

<p>Area2 = (2b/3)(3h/4)/2 = bh/4 = (1/2)(Area), answer is 1/2.</p>