一个基本图形的运用和变式

Application of a Basic Figure and Its Flexible Form

通过对相似三角形中的一个基本图形的发现、变式、拓展的研究及其在教学中的体会，阐述基本图形的重要性和必要性，从而达到发展学生的思维，提高解题能力的目的．

This article, through the study of the discovery of a basic figure in the similar triangle, its flexible and related forms, expounds the importance and necessity of the basic figure so as to develop students' thinking and raise their ability in solving problems.