2017年9月27日SAT官方每日一题---数学选择.

　　下面是2012年9月27日的SAT官方每日一题的内容，是关于数学方面的，题型是选择。SAT官方每日一题是collegeboard每天都会发布的题目，关于SAT考试的三个部分的各个题型。下面我们就一起来看一下这个SAT官方每日一题吧。

　　SAT官方每日一题之数学---选择：

　　直接获取澳际名师服务点击进入>>>>有问题?找免费的澳际专家咨询! 或者通过在线咨询处留言，把您最关心的问题告诉我们。

　　Mathematics > Standard Multiple Choice

　　Read the following SAT test question and then click on a button to select your answer.

　　The histogram above shows the distribution of 31 black cherry trees, by height. For example, the ltmost bar represents the black cherry trees that are at least 60 feet, but not less than 65 feet, in height. Based on the histogram, which of the following can be the average (arithmetic mean) height of the 31 black cherry trees?

　　Answer Choices

　　(A) 70 feet

　　(B) 72 feet

　　(C) 74 feet

　　(D) 78 feet

　　(E) 80 feet

　　The correct answer is C

　　Explanation

　　The histogram does not give the recorded heights for each cherry tree, but rather the intervals in which the heights lie. Thus, to find possible values for the average (arithmetic mean) height, one can find lower and upper bounds for the average height by calculating the averages of lower and upper interval bounds of the histogram with the frequencies given. A lower bound for the average, found by using the value at the lt endpoint of the interval, is feet, and so feet would be an upper bound for the average height. Therore, the average height of the 31 black cherry trees can be between 72.74 feet and 77.74 feet. Of the choices given, only 74 feet can be a possible value for the average height of the 31 black cherry trees.

　　下面为大家提供一些和这些SAT官方每日一题相似的题目，供大家练习：

　　Read the following SAT test question and then click on a button to select your answer.

　　In the figure above, O is the center of the circle and triangle A B O is equilateral. If the sides of triangle A B O are of length 6, what is the length of line B C?

　　(A) 3 times square root 3

　　(B) 4 times square root 3

　　(C) 6 times square root 3

　　(D) 9

　　(E) 12

　　The correct answer is C

　　Explanation

　　Choice (C) is correct. Since triangle A B O is equilateral, each of its angles has measure

　　60 degrees. It follows that angle B O C has measure 120 degrees. Since line O B and line O C are radii of the same circle, they are of equal length, and so delta O C B is isosceles. Hence angle O B C and angle O C B each have measure 30 degrees. Thus angle A B C has measure 60 degrees + 30 degrees = 90 degrees, and so triangle A B C is a 30 degrees minus 60 degrees minus 90 degrees right triangle. Since line A B, the side opposite the 30 degrees angle in triangle A B C, is of length 6, it follows that line B C, the side opposite the 60 degrees angle, is of length 6 times square root 3

　　以上就是关于2012年9月27日SAT官方每日一题中数学部分的详细内容，包括了题目和选项以及答案，后面附有一道相关的练习题。大家可以在备考SAT的过程中关注SAT每日一题的内容，这样就可以更好有不间断的练习，也就能在日积月累的过程中得到提高。