圆由曲线围成。圆与方、曲与直虽然是对立的,但在一定条件下可相互转化。圆面积的教学,如能正确揭示方圆、曲直之间的内在联系与变化规律,从中渗透极限思想,学生就能理解和掌握圆面积计算公式,并逐步形成辩证唯物主义思想与空间想象能力。具体教法如下: 首先,教师问:“如何表示圆周长的一半?”(此问答案不一,有利于考察和开发学生智力。) Circle formed by the curve. Round and square, song and straight though is the opposite, but under certain conditions can be transformed into each other. The circular area of ​​teaching, if we can correctly reveal the inherent relationship between the radius and the curvature of the law, from which to infiltrate the limits of thinking, students can understand and grasp the circular area formula, and gradually form the dialectical materialism and space imagination. Specific teaching is as follows: First, the teacher asked: “How to represent the circumference of the half?” (This question and answer different, is conducive to the study and development of student intelligence.)