在几何图形的海洋中畅游,我深深地感到,画一画是一种很好的学习方法,不信,你瞧:一次,我遇到了这样一道题目:有一张长方形纸,长21分米,宽18分米。如果要用它剪直角边分别是5分米和4分米的三角形小旗,最多可以剪多少面?通过画图,我发现以前学习的大面积中包含几个小面积的方法对这道题已经不适用了,因为要考虑实际情况。老 Take a dip in the ocean of geometry. I feel deeply that drawing a picture is a good way to learn. Believe it or not, once, I encountered such a question: there is a piece of rectangular paper, 21 meters long, 18 meters wide. If you want to use it to cut the right side of the triangle are 5-meter and 4-meter triangular flag, the maximum number of surface can be cut? Drawing, I found that previously learned large area contains several small area of ​​the problem Not applicable, because we must consider the actual situation. old