2011版《数学课程标准》提出了模型思想.模型思想是一种基本的数学思想,它在初中数学教学中有着重要意义.几何模型的重要性体现在,能够使我们在解决相关问题时迅速找到思维的切入点,少走弯路.本文介绍“三等角必相似几何模型”的应用.一、建立模型模型1如图1,点E在线段AB上,∠CED=∠A=∠B=α,则△ACE∽△BED.证明因为∠BEC是△ACE的外角,所 The 2011 edition of “Mathematical Curriculum Standards” put forward the model idea.Model thought is a kind of basic mathematical thought, which is of great significance in the junior middle school mathematics teaching.The importance of the geometric model is reflected in that we can quickly find the solution to related problems Thinking of the entry point, take detours. This article describes the “Third-class angle must be similar to the geometric model.” First, the establishment of the model model 1 As shown in Figure 1, point E on the line AB, ∠ CED = ∠ A = ∠ B = α, then △ ACE ∽ △ BED. Prove that because ∠ BEC is the outer corner of △ ACE, the