梯形是并列于平行四边形的又一类特殊的四边形,它是“空间与图形”领域研究的重要对象之一.根据知识构建模式,梯形是在学习了三角形和平行四边形后学习的几何图形,因此,学习梯形,不仅要理解梯形概念,了解梯形分类,熟知等腰梯形的性质,从而把握梯形的实质,更重要的是,要能利用化归的思想方法,利用平移、旋转等作出辅助线,进行图形分割、拼接,把梯形的问题转化为我们已经学 Trapezoid is another special type of quadrilateral juxtaposed to a parallelogram, which is one of the important objects in the field of “space and graph.” According to the pattern of knowledge building, trapezoid is the geometry learned after learning triangle and parallelogram Therefore, to learn trapezoid, not only the concept of trapezoid, the trapezoid classification, and the properties of isosceles trapezium should be understood, but also the essence of trapezoid should be understood. More importantly, it should be possible to make use of the methods of conversion, rotation, etc. Line, the graphics division, stitching, the trapezoidal problem into what we have learned