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贵刊曾多次刊登用构图法解题的文章,其实在小学数学题中有很多题目都可以利用构图法来解答,下面再来谈几例用构造几何图形的方法来解答的题目。一、构造长方形例1 两个工程队计划一个月修筑680米的公路,实际两个工程队一个月共修筑798米,第一队比本队的任务多修筑20%,第二队比本队的任务多修筑15%,两队原来任务各是多少米?分析:根据题意先画出图1,从图1中无法找出实数量与倍数量的对应关系,所以假设两队都比本队任务多修20%,把图1转变成图2,构成长方形,那么实际完成的就不是798米,而是680×(1+20%)米,这样假设比实际修筑的798米多[680×(1+20%)-798]米,原因是第二队只多修15%,因
Your magazine has published articles that use composition methods for solving problems many times. In fact, there are many topics in elementary mathematics that can be solved by using composition methods. Here are a few more examples of problems with constructing geometric figures. First, the construction of rectangular Example 1 two project team plans to build a 680-meter highway a month, the actual two engineering team a total of 798 meters a month to build the first team than the task of building more than 20% of the team, the second team than the team Of the task more than building 15%, the two teams the original task is how many meters? Analysis: According to the problem first to draw Figure 1, from Figure 1 can not find the correspondence between real number and times, so the two teams are more than the capital 20% more team work, the figure 1 into Figure 2, forming a rectangle, then the actual completion is not 798 meters, but 680 × (1 + 20%) meters, this assumption than the actual construction of more than 798 meters [680 × (1 + 20%) - 798] meters, because the second team only repair more than 15% due to