“人说几何很困难,难点就在辅助线。辅助线,如何添?把握课本和教参。还要刻苦加钻研,找出规律凭经验”。走进七年级下半学期的学生,学习第五章“相交线与平行线”就会遇到图形与几何中一大难题——添加辅助线。七年级学生对做辅助线总是摸不着头脑,没有思路。殊不知这里有一种经常做的辅助线,就是平行线里画平行,即见折点画平行线。而这一辅助线的画法也来源于人教版《义务教育教科书·数学》七年级下册第23页综合运用中第7题的第(2)问(如例1)。 “People say that geometry is very difficult, difficult in the auxiliary line. Auxiliary line, how to add? Grasp the textbooks and teaching parameters. Into the seventh grade students in the second semester, learning the fifth chapter ”intersecting lines and parallel lines “ will encounter a big problem in graphics and geometry - add auxiliary line. The seventh grade students always feel helpless, there is no way of thinking. As everyone knows there is a kind of auxiliary line that is often done, that is, parallel lines are drawn in parallel, that is, the turning point is drawn parallel to the line. The auxiliary line of drawing also comes from the PEP Edition ”Compulsory Education Textbook · Mathematics" Volume II, Volume 23 comprehensive utilization of the seventh question (2) asked (such as Example 1).