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1.教材分析.1.1教材地位.本节课是北师大版九年级上册第四章“图形的相似”第7节“相似三角形的性质(第1课时)”.本课是在全等三角形、成比例线段、特殊的平行四边形、相似三角形的判定的基础上学习的,又是后面学习锐角三角函数、圆的基础.1.2教学目标.1.2.1能从具体情境中知道相似三角形对应高、对应中线、对应角平分线的比等于相似比,通过对相似三角形对应线段比的讨论,感受相似三角形对应线
1. Textbook analysis .1.1 textbook status. This class is the fourth edition of the Beijing Normal University edition of the ninth grade “Similarity of graphics ” Section 7 “similar to the nature of the triangle (the first class) ” Based on congruent triangles, proportional segments, special parallelograms, similar triangles, learning is based on the learning of acute trigonometrical trigonometrical functions and circles.1.2 Teaching Objectives .1.2.1 It is possible to learn from similar situations that similar Corresponding to the high triangle, corresponding to the median line, the corresponding angle bisector equals to the similarity ratio. Through the discussion of the similarity of the corresponding segments of the triangle, the feeling of similar triangles corresponding to the line