题干

八年级某班数学实验课安排测量操场上旗杆的高度.小聪同学经过认真思考,研究出了一个可行的测量方案:在某一时刻测得旗杆AB的影长BC和∠ACB的大小,然后在操场上画∠MDN,使得∠MDN=∠ACB,在边DM上截取线段DE=BC,再利用三角形全等的知识求出旗杆的高度,请完成小聪同学的测量方案,并把图形补画完整,说明方案可行的理由.


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答案(点此获取答案解析)

解:如图所示:

过点E作GE⊥DM,垂足为E,此时EG=AB,

理由:在△ACB和△GDE中

ACB=GD

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