论文部分内容阅读
一、复习旧知师:同学们好!前面我们结束了对相似三角形这一章的学习,那么,谁能告诉我,什么叫相似?生1:两角相等的三角形相似。生2:两角对应相等的两个三角形相似。生3:应该是对应角相等,对应边成比例的三角形叫相似三角形。生4:形状相同的三角形叫相似三角形。师:还有不同意见吗?(学生无人再回答)师:同学们,相似用生活语言理解是:形状相同的图形,用数学语言理解就是:对应角相等,对应边成比例的图形叫相似图形。【点评】强化记忆,巩固提高(多媒体课件出示下图)下面请同学们看屏幕:如图所示:如果△ABC和38
First, the review of the old division: the students are good! In front of us ended the study of the chapter similar to the triangle, then, who can tell me, what is the similarity? Health 1: Similar triangles triangle. Health 2: The two triangles that correspond to equal angles are similar. Students 3: The corresponding angle should be equal, corresponding to the side of the triangle is called a similar triangle. Students 4: the same shape of the triangle called similar triangles. Teachers: Do you have any other opinions? (Students no answer) Teacher: Students, similar to the language of life is understood: the same shape of the figure, understood in mathematical language is: the corresponding angle is equal to the corresponding side of the graphics is similar to the proportion of similar Graphics. 【Comments】 strengthen memory, consolidation and improvement (multimedia courseware to show below) Please follow the students to see the screen below: As shown: If △ ABC and 38