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一、基本概念相似形中主要内容包括成比例线段和相似三角形.成比例线段中的主要概念有线段的比、成比例线段、第四比例项、比例中项和黄金分割.主要定理有比例的基本性质、合比性质、等比性质、平行线分线段成比例定理和推论、三角形一边平行线的判定定理. 相似三角形中的主要概念有相似三角形和相似比.主要定理有三角形相似的判定定理、直角三角形相似的判定定理、相似三角形的性质定理.
First, the basic concept of similarity The main content of the similarity includes proportional line segments and similar triangles. The main concepts of proportional line segments are ratios of wired segments, proportional segments, fourth proportional terms, proportional middle terms, and golden sections. The main theorems are proportional. Basic properties, congruent properties, equal ratio properties, proportional theorem and deduction of parallel line segments, decision theorem of parallel lines on one side of a triangle. The main concepts in similar triangles have similar triangles and similarity ratios. The main theorem has a triangular similarity theorem , the similarity theorem of the right triangle, the property theorem of the similar triangle.