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近年来,与多面体相关的外接球的表面积或体积问题频繁出现在高考试卷中,风头正劲,其难点在于确定球心的位置,学生普遍对这类问题信心不足,本文结合实例,全面介绍确定球心的方法,希望对大家的学习有所借鉴.1球心为长方体对角线的中点例1如图1,在正三棱锥S-ABC中,M是SC的中点,且AM⊥SB,底面边长AB=槡2 2,则正三棱
In recent years, the polygons related to the surface area of the ball or volume problems frequently appear in the exam papers, limelight, the difficulty is to determine the location of the ball center, students generally lack confidence in these issues, this article with examples, a comprehensive introduction to determine Ball center of the method, I hope we learn from the experience .1 center of the ball as the center of the rectangular parallelepiped Example 1 In the regular triangular pyramid S-ABC, M is the midpoint of the SC, and AM ⊥ SB , The length of the bottom side AB = 槡 2 2, is three-edge