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课标数学选修4-1《几何证明选讲》将原来初中平面几何删减的圆的有关内容(如弦切角、切割线、相交弦)又添加进来.这些内容对高中生来说是新知识,由于安排课时少,解答相关问题时常感没有思路.现就与圆有关的辅助线归纳如下.一、与直径有关的辅助线题中有直径或可以作出直径时,常作出直径所对的圆周角(直角),构造直角三角形中的射影模型;或把与直径垂直的线段补成弦,构造垂径、相交弦.
Course Maths Elective 4-1 The Geometrical Proofs Lectures add to the original circle of the original middle school geometry truncations (such as chipping, cutting lines and intersection chords), which are new knowledge for high school students , Due to the arrangement of hours less frequently to answer the relevant questions without thinking. Now on the circle-related auxiliary lines are summarized as follows. A diameter-related auxiliary questions in the diameter or diameter can be made often make the diameter of the circle Angle (right angle) to construct a projective model in a right-angled triangle, or to make a line segment perpendicular to the diameter to make up a chord to construct a dip and intersect the chord.