Tham khảo tài liệu 'the sat math section 5', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | THE SAT MATH SECTION 12. a. This problem is difficult if you make it diffi- cult but it s easy if you make it easy. The easiest way to do this problem is to calculate the mean median and mode for the data set. Remember The mean is the same as the average. The median is the middle number of data. First you must order the numbers from least to greatest. The mode is the most frequently occurring number. So the mean equals 5 7 5 5 7 6 The median if found by rearranging the numbers in the data set as shown is 5 5 6 7 7 . Therefore the median is 6. The mode is the most frequently occurring number. In this data set there are two numbers that appear most frequently 5 7 . Now inspect the answers. You will quickly see that choice a is correct The mean median because 6 6. 13. c. You have to figure out ifXY and YZ are per- pendicular. The key thing to remember here is that perpendicular lines intersect to form right angles. If you can find a right angle at the point that XY and YZ intersect then you know that the two segments are perpendicular. In Figure 1 if XY and YZ are perpendicular then AXYZ is a right triangle because it contains a right angle at Y. In AXYZ you are given three sides. If AXYZ is a right triangle then the Pythagorean theorem should hold true for these three sides. Leg 1 2 Leg 2 2 Hypotenuse 2 6 2 8 2 10 2 Note 10 is the hypotenuse because it is across from the largest angle of the triangle. 36 64 100 100 100 AXYZ is a right triangle and likewise XY is perpendicular to YZ because the Pythagorean theorem is true for Figure 1. In Figure 2 you are given the two angles of AXYZ. If a third angle measures 90 then zY is a right triangle. Thus XY is perpendicular to YZ. mZX mZY mZZ 180 since the sum of the angles of a triangle 180. 25 x 65 180 90 x 180 Therefore x 90 . zY is a right angle and XY is perpendicular to YZ. Thus XY is perpendicular to YZ in both figures. The answer is choice c. 14. d. The first thing that you should realize is that x and y are both .
