<p>I just finished a practice test
and still don't get these few problems ::</p>
<p>Section 2</p>
<h1>5, 14, 18</h1>
<p>Section 8</p>
<h1>16</h1>
<p>All problems can be found on
<a href="http://www.collegeboard.com/prod_downloads/prof/counselors/tests/sat/2007-08_sat_preparation_booklet.pdf%5B/url%5D">http://www.collegeboard.com/prod_downloads/prof/counselors/tests/sat/2007-08_sat_preparation_booklet.pdf</a></p>
<p>If someone could explain how to do them,
it would mean a whole lot to me.
Thanks!! :)</p>
<ol>
<li>Take a moment and graph the problem. You see that points F and H lie the same distance from point G and that you can connect the dots to form a semi circle. Look on your graph and estimate the midpoint. (1,1) looks about right. Since F and H also have the same y value, you can conclude that FH is a diameter and the midpoint of this line will be the center. Use the midpoint formula:</li>
</ol>
<p>(-2 + 4)/2 = 1
(1 + 1)/2 = 1
(1,1) = your answer</p>
<ol>
<li><p>You just need the left side to be less than one. 0<1, so let’s set -2x+1=0 (the absolute value signs can be dropped since abs(0)=0). We get x=.5, which works as a value for x. </p></li>
<li><p>Since this function is some sort of quadratic/square function, y and x will always change inversely. However they will have an equilibrium point. Since X<Y or X=Y, and you want the minimum value of y, in which case x=y. Because of this, you can change both variables to the same variable. </p></li>
</ol>
<p>(2a)^2 -0 >,= 25</p>
<p>4a^2 >,= 25
a^2 >,= 25/4
a >,= 5/2 which gives you your correct answer</p>
<ol>
<li>Okay, so draw yourself a triangle with the correct sides. When they say that CP is perpendicular to AB, they are essentially asking you to find the height of the triangle for that orientation. So flip that triangle upside down with AB on the bottom. Once you draw your CP, which forms two 90 degree angles with AB, you’ll see that you have a new right triangle formed. The hypotenuse of this triangle is 3. This means that both of the other sides have to have lengths shorter than three. The only choice smaller than three is A (2).</li>
</ol>
<p>and nice explanations :D</p>
<p>Section 9, # 15 in
<a href=“College Board - SAT, AP, College Search and Admission Tools”>College Board - SAT, AP, College Search and Admission Tools;
<p>I know the answer is decrease (choice C, D, or E)
but does anyone know how to find the value in which it decreases?</p>
<p>Thanks a bunches!!</p>
<p>You are right that it’s decrease, and simply, just translate what they gave you into math terms. 1900 = 0 decades after 1900. Let’s name that value x. 1920 = 2 decades after 1900. Let’s name that value y.</p>
<p>x - y = the answer.</p>
<p>x is equal to:
f(t) = 500<em>(.81)^0
f(t) = 500</em>1
f(t) = 500</p>
<p>y is equal to:
f(t) = 500<em>(.81)^2
f(t) = 500</em>.6561
f(t) = 328.05</p>
<p>x - y is equal to:
500 - 328.05
171.95, or 172</p>
<p>So the decrease from 1900 to 1920 is 172. The answer they have is choice C, a decrease of 180, which is the closest to 180. And since it says about, you want to estimate anyway.</p>
<p>oic, thanks AzureStar =]</p>
<p>No problem! I hope it was clear enough though because I’m not so good at explaining things.</p>