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这是一节八年级全等三角形的习题课.按计划本节打算处理6题.处理完2题后,看到孩子们兴趣正浓,跳到较有难度的11题.△ABC中,AD是他的角平分线.求证:S△ABD∶S△ACD=AB∶AC(如图1所示)根据教材提示:(DE⊥AB,DF⊥AC.垂足分别为E,F)部分孩子能很快完成.我让其中一个孩子简要说明思路和解题方法.看到大部分孩子掌握较好,便将题目进一步拓展.
This is an eighth-grade congruent triangle exercise class .According to the plan this section intends to deal with 6. After finishing two questions, see the children are interested in strong, jump to the more difficult 11 questions. △ ABC, AD Is his angle bisector. Verification: S △ ABD: S △ ACD = AB: AC (as shown in Figure 1) According to the textbook tips: (DE ⊥ AB, DF ⊥ AC. Can finish very quickly.I let one of the children briefly explain the way of thinking and problem solving.It can be seen that most children have a good grasp and the topic will be further expanded.