作者deathcustom (Full House)
看板Math
标题Re: [中学] 请问几题小学生的算法
时间Thu Jan 16 14:26:04 2025
※ 发信站: 批踢踢实业坊(ptt.cc), 来自: 203.204.210.81 (台湾)
※ 文章网址: https://webptt.com/cn.aspx?n=bbs/Math/M.1737006330.A.E2A.html
※ 编辑: wallowes (203.204.210.81 台湾), 01/16/2025 13:46:58
※ 编辑: wallowes (203.204.210.81 台湾), 01/16/2025 13:50:56
1F：推 deathcustom : 我原来写得那麽复杂就是因为要考虑到小学生甚麽都 01/16 14:09
2F：→ deathcustom : 没学过(相似三角形的特性、中线的特性都没学过) 01/16 14:10
3F：→ deathcustom : 要不然FG线段被三等份，随便就可以算完 01/16 14:10
4F：→ wallowes : 那我就不懂了，我连筝型都没印象了 01/16 14:14
5F：→ musicbox810 : d大可以写一下怎麽证明FG被三等份吗?谢谢 01/16 14:15
It's prima facie that FG is equally divided into 3 segments FQ,QR, and RG, and
here is the proof:
1) draw a line FC
2) in the triangle BCF, G is the mid point of BC, and P is the mid point of FC.
3) Hence, BP and FG are both medians of the triangle BCF.
4) accordingly, FG is divided into FR and RG and the ratio therebetween is 2:1.
Similarly
FQ:QG=1:2
Therefore, FQ:QR:RG = 1:1:1#
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6F：→ musicbox810 : 谢谢d大 01/16 14:37