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一道SAT数学题解答方法

  下面是一道关于几何方面的SAT数学题的解答方法详细分析,来自SAT考试的官方网站collegeboard。这是一类关于分析可能性的SAT数学题,这种题在SAT数学考试当中经常会见到,考察大家考虑问题是否全面的能力。下面是详细内容。

  

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  If two sides of the triangle above have lengths 5and 6, the perimeter of the triangle could be which of the following?

 

   Roman numeral 1. 11

  Roman numeral 2. 15

  Roman numeral 3. 24

 

  Answer Choices

  (A) Roman numeral 1only

 

  (B) Roman numeral 2only

 

  (C) Roman numeral 3only

 

  (D) Roman numeral 2and Roman numeral 3only

 

  (E) Roman numeral 1, Roman numeral 2, and Roman numeral 3

 

  The correct answer is B

  Explanation

  Difficulty: Hard

  In questions of this type, statements Roman numeral 1, Roman numeral 2, and Roman numeral 3should each be considered independently of the others. You must determine which of those statements could be true.

 

  Statement Roman numeral 1cannot be true. The perimeter of the triangle cannot be 11, since the sum of the two given sides is 11without even considering the third side of the triangle.

 

  Continuing to work the problem, you see that in Roman numeral 2, if the perimeter were 15, then the third side of the triangle would be 15 minus (6 + 5), or 4. A triangle can have side lengths of 4, 5, and 6. So the perimeter of the triangle could be 15.

 

  Finally, consider whether it is possible for the triangle to have a perimeter of 24. In this case, the third side of the triangle would be 24 minus (6 + 5) = 13. The third side of this triangle cannot be 13, since the sum of the other two sides is not greater than 13. By the Triangle Inequality, the sum of the lengths of any two sides of a triangle must be greater than the length of the third side. So the correct answer is Roman numeral 2only.

  以上就是这道SAT数学题的详细解答方法的全部内容,对这道SAT数学题中的每一个可能的答案都进行了分析。大家在备考的时候可以按照上面所列的方法进行,这样在考试的时候就可以更加快速而且有效率的解答相关的SAT数学题目了。

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