一、知识要点1．等腰三角形的定义、性质和判定．2．等边三角形的定义、性质和判定．3．直角三角形的定义、性质和判定．4直角三角形全等的判定（HL）．5．线段垂直平分线的性质和判定．6．角争分线的性质和判定．7．轴对称的定义和性质．二、解题指导例1填空：（1）若等腰三角 First, knowledge points 1. The definition, nature, and determination of isosceles triangles. 2. The definition, properties, and determination of equilateral triangles. 3. Definition, properties, and determination of right triangles. 4 Right triangle congruent determination (HL). 5. The nature and determination of the line perpendicular bisector. 6. The nature and determination of the corner line. 7. Axisymmetric definition and properties. Second, the problem-solving guide example 1 fill in the blank: (1) if the isosceles triangle