YLL討論網

由 **J+W** 於星期四五月 04, 2006 5:37 pm

有兩位朋友先解了#ed_op#BR#ed_cl##ed_op#BR#ed_cl##ed_op#A href="http://www.mathland.idv.tw/talkover/memo.asp?srcid=19327&bname=ASP"#ed_cl#http://www.mathland.idv.tw/#ed_op#FONT color=#000000#ed_cl#talkover#ed_op#/FONT#ed_cl#/memo.asp?srcid=19327&bname=ASP#ed_op#/A#ed_cl# #ed_op#BR#ed_cl##ed_op#BR#ed_cl#整理如下：#ed_op#BR#ed_cl#∵∠BDE=19°，∠DBE=45°-19°=26°，#ed_op#BR#ed_cl#∴∠BED=180°-19°-26°=135°#ed_op#BR#ed_cl#而反角∠BCD=270°，所以B、E、D共圓，圓心在C#ed_op#BR#ed_cl#∴ 線段DC=線段EC=線段BC#ed_op#BR#ed_cl#△DCE及△ECB 為等腰三角形#ed_op#BR#ed_cl##ed_op#BR#ed_cl#又∠EDC=∠EDB+∠BDC#ed_op#BR#ed_cl#=19° +45°=64°#ed_op#BR#ed_cl##ed_op#BR#ed_cl#∠EDC=∠DEC=64° #ed_op#BR#ed_cl#∠DCE=180°－2(64°)=52° #ed_op#BR#ed_cl# 左鍵: 點擊縮放; 右鍵: 觀看原圖

#ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#

由 **kai** 於星期四五月 04, 2006 4:44 pm

#ed_op#DIV#ed_cl#顯然C為BED外心(用同一法)#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#180-19-45-19-45=52度#ed_op#/DIV#ed_cl#

由 **100** 於星期三五月 03, 2006 10:11 pm

#ed_op#DIV#ed_cl##ed_op#P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#在正方形#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABCD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#中，連#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#BD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#，#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#E#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#為Δ#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#內一點，連#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#EB#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#、#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#EC#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#、#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ED#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#，若∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#＝∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#BDE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#＝#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#19#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#度，試求∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#DCE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#的度數。#ed_op#/SPAN#ed_cl##ed_op#/P#ed_cl##ed_op#/DIV#ed_cl#

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[quote="100"]#ed_op#DIV#ed_cl##ed_op#P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#在正方形#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABCD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#中，連#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#BD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#，#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#E#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#為Δ#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABD#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#內一點，連#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#EB#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#、#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#EC#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#、#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ED#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#，若∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#ABE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#＝∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#BDE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#＝#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#19#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#度，試求∠#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US#ed_cl#DCE#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"#ed_cl#的度數。#ed_op#/SPAN#ed_cl##ed_op#/P#ed_cl##ed_op#/DIV#ed_cl# [/quote]