If you are reading this in an email you received from me, do not click the link to sat.collegeboard.org below. Use the link to my website that is farther down on the email. If you are seeing this in my blog, dco the SAT Question of the Day by clicking on this link:
http://sat.collegeboard.org/practice/sat-question-of-the-day?src=R&questionId=20130528 (This link takes you to today’s question. If you use my archive, you will see the question related to my SAT explanation for that date.)
The answer is C. Similar triangles are almost always on the test. Usually they are signaled by having one triangle inside of another with one side of the smaller interior triangle being parallel to a side of the larger triangle. The SAT’s explanation shows that situation with the fence post being parallel to the boy’s body. The triangle created by the fence post is inside the triangle created by the boy’s body. The fact that the two triangles are right triangles is irrelevant. In other words, similar triangles do not have to be right triangles. They can be any shape as long as one side of an interior triangle is parallel to a side of the exterior/larger triangle. Similar triangles can also be signaled by telling you one side of the smaller, interior triangle and one side of the larger triangle have the same sized angles which are shared with a common side. (Refer to page 455, number 10, in the Official SAT Study Guide.) They may also signal similar triangles by telling you the sides of the interior, smaller triangle divide the sides of the larger triangle in half or thirds, etc. (page 860, number 12). When you see any of these signals remember the big triangle and little triangle are in proportion to one another.
Similar triangles are the same shape since they share the same sized angles. However, they are of different sizes that are in proportion to one another. In this question, Miguel’s shadow is 1/3 of his height; so, the fence post’s shadow will be 1/3 of its height. Since the shadow is t, the fence post has to be 3 times as tall, 3t.
Let’s see what we can do to out-trick the ACT tricksters.
http://www.act.org/qotd/ (The ACT staff does not put a date on their questions so if you click on an archived blog, you’ll get today’s question and the old explanation. Sorry. The SAT staff has dated their questions; so, the archive is helpful. The ACT folks simply don’t do that.)
The answer is B. This one isn’t very tricky. Based on the table, we can see the pH is getting 0.5 smaller for every 5cm in depth we go. From 20cm to 35cm, we are getting 15cm or 3 times 5cm deeper. Three units deeper means the pH has to change 3 times -0.5 which gets us to 3.5 (5.0 – 1.5 = 3.5). This is very straight forward. No tricks here.
Be sure you are practicing reading and using charts and graphs from real ACT tests to prepare. Don’t worry about reviewing science content; they give you all the science you need on the test. The challenge is to use their data quickly so that you can answer their questions.
Have a great week.