<p>About a month ago, i remember doing a problem EXACTLY like this and getting it... now i just cant do it.</p>
<p>(Look up the figure)</p>
<p>The figure above shows the route of Diane's trip from her house to her job. Diane travels 16 miles from A to B, 15 miles from B to C, and 4 miles from C to D. If she were able to travel from A to D directly, how much shorter, in miles, would the trip be?</p>
<p>A. 5
B. 8
C. 10
D. 11
E. 15</p>
<p>I guessed correctly by finding the distance from A to C and narrowing it down to C and D... but I'd like to know how to do it</p>
<p>Remember this is the SAT, so you can expect most figures to test your knowledge of right triangles. </p>
<p>In this case, you should try to redraw the graph to get a right triangle. Simply drop the distance CD (4) next to AB (16) and then move BC to the right by 4. The position of D did obviously not change. What do you get now? Two sides of a right triangle of 15 and 20. BTW, the numbers 16 and 4 are dead giveaways when coupled with 15. Since you SHOULD have memorized the various multiples of 3,4,5 triangles, the number 25 should jump at you. </p>
<p>So what is the shortest route? 25. The original route is 16+15+4 or 35. The difference is 10.</p>