<p>I have a question about a problem from the official sat practice test of 07-08: <a href=“College Board - SAT, AP, College Search and Admission Tools”>College Board - SAT, AP, College Search and Admission Tools;
<p>Go to page 74, #5. The answer is D, but why can’t any of the other graphs be the answer also? I can’t see why not… they are all straight lines.</p>
<p>It HAS to pass through the origin. y = kx where k is a constant for directly proportional lines. when x = 0, y also = 0 from this equation. This means D is the only one that works.</p>
<p>Alright, thanks. I have another question, same link. Pg 76, #16. No idea how to do it.</p>
<p>For #16, I just figured that since CP is going to be perpendicular to AB, it divides ABC into two right triangles. Then the hypoteni would be are BC, length 3 and AC, length 6. Since CP is a leg of both right triangles it has to be shorter than the hypoteni, and 2 is the only choice smaller than both 3 and 6.</p>