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《中小学数学》(小学版)2014年第1-2期刊登了《小学数学四边形的二分法及其面积计算的一点思考》一文(以下简称《思考》),笔者读后,感触颇多,现略谈拙见。不妥之处,敬请赐教。一、平行四边形是特殊的梯形吗1.关于梯形的定义。《思考》指出:“如果我们以‘有无对边平行’这个标准对四边形分类,可以把四边形分成两类:1.设有对边平行的四边形;2.有对边平行的四边形。然后,把一组对边平行的四边形叫做梯形,有一组对边平行且相等的梯形叫做平行四边形;有一组对边平行且相
”Primary and Secondary Mathematics“ (Elementary School Edition) 2014 No. 1-2 published a ”primary school mathematics quadrilateral dichotomy and its area calculation of thinking“ one article (hereinafter referred to as ”thinking“), the author read, feel a lot, Now humble opinion. Inappropriate, please enlighten me. First, the parallelogram is a special trapezoid 1. On the definition of trapezoid. ”Thinking“ states: ”If we classify the quadrilaterals according to the criterion of whether there is parallelism or not, we can divide the quadrilaterals into two categories: 1. a quadrilateral that is parallel to the sides, a quadrilateral that is parallel to the sides, and then , A set of parallel to the side of the quadrangle called trapezoid, a group of parallel and equal to the side of the trapezoid called the parallelogram; a group of parallel to the side and phase