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數學競賽幾何題形請教

數學競賽幾何題形請教

長方形\(ABCD\)中,\(\overline{AB}=5\),\(\overline{BC}=4\)。點\(E\)在\(\overline{AB}\)邊上且\(\overline{EB}=1\),點\(G\) 在\(\overline{BC}\)邊上且\(\overline{CG}=1\),點\(F\)在\(\overline{CD}\)邊上且\(\overline{DF}=2\)。若線段\(\overline{AG}\) 及\(\overline{AC}\)分別交\(\overline{EF}\)於\(Q\)及\(P\),則\(\displaystyle \frac{\overline{PQ}}{\overline{EF}}\)之值為何?
(A)\(\displaystyle \frac{\sqrt{3}}{16}\) (B)\(\displaystyle \frac{\sqrt{2}}{13}\) (C)\(\displaystyle \frac{9}{82}\) (D)\(\displaystyle \frac{10}{91}\) (E)\(\displaystyle \frac{1}{9}\)
我是用定坐標解出的, 請教以相似解題方法.謝謝您

114.4.18補充
長方形\(ABCD\)中,\(\overline{AB}=5\),\(\overline{BC}=6\)。點\(E\)在\(\overline{AB}\)邊上且\(\overline{EB}=2\),點\(G\)在\(\overline{BC}\)邊上且 \(\overline{CG}=1\),點\(F\)在\(\overline{AD}\)邊上且\(\overline{AF}=2\)。若線段\(\overline{DE}\)及\(\overline{DB}\)分別交\(\overline{FG}\)於\(P\)及 \(Q\),則\(\displaystyle \frac{\overline{PQ}}{\overline{FG}}=\)   
(110嘉義高中資優班,https://www.cysh.cy.edu.tw/p/403-1008-242-1.php)

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110嘉義高中資優班.pdf (337.69 KB)

2025-4-18 13:19, 下載次數: 684

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回覆 1# aliher327 的帖子

答案是(D)

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回覆 1# aliher327 的帖子

設直線 AG 交直線 DC 於 H
易知 CH = 5/3

EQ / FQ = AE / HF = 6/7
設 EQ = 6x,FQ = 7x,PQ = y

EP / FP = AE / CF = 4/3
(6x + y) / (7x - y) = 4/3
y = (10/7)x

PQ / EF = (10/7) / (6 + 7) = 10/91

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回覆 3# thepiano 的帖子

非常感恩PIANO老師

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