课本中的几何图形都是比较有代表性的,但这些图形并不能以一概全.若能对课本中的例(习)题图形进行部分或整体的拓变,会得出各种不同的变式图形,这对培养学生思维的全面性是非常有利的,有助于学活数学.下面举例说明这一事实. Geometry in the textbooks are all representative, but these figures cannot be summarized. If we can partially or entirely expand the example (learning) graphics in textbooks, we will get a variety of changes. The graphic, which is very beneficial to the comprehensiveness of students’ thinking, is helpful for learning mathematics. Here is an example to illustrate this fact.