YLL討論網

#ed_op#DIV#ed_cl#就是畢氏定理啊......#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#此梯形可分成一個長方形和直角三角形,#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#再用畢氏定理......#ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl#lcflcflcf，我明白了????#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#不過aa2191943，我想知道為什麼'B = √[(O#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#O#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#)#ed_op#SUP#ed_cl#2#ed_op#/SUP#ed_cl#-(AO#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#-BO#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#)#ed_op#SUP#ed_cl#2#ed_op#/SUP#ed_cl#] = 2√3，是定理嗎，若是，是什麼???#ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl#我呆掉了......#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#請問是哪兩個三角形相似......#ed_op#/DIV#ed_cl#

??? 寫到:#ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl#剛好路過....還是國一生,不太明白#ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl#lcflcflcf，為什麼(1+a)/1=(5+a)/3 ???? 還想知道aa2191943怎樣算出2開方3???#ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl#相似三角形#ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl##ed_op#DIV#ed_cl#圓外一點到圓的切線等長#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以: QP = QA = QB = AB/2#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#O#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#A 與 O#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#B 同時垂直 AB, 所以兩線平行#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以四邊形 AO#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#O#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#B 為梯形#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#AB = √[(O#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#O#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#)#ed_op#SUP#ed_cl#2#ed_op#/SUP#ed_cl#-(AO#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#-BO#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#)#ed_op#SUP#ed_cl#2#ed_op#/SUP#ed_cl#] = 2√3#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以 PQ = AB/2 = √3#ed_op#/DIV#ed_cl##ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl#剛好路過....還是國一生,不太明白#ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl#lcflcflcf，為什麼(1+a)/1=(5+a)/3 ???? 還想知道aa2191943怎樣算出2開方3???#ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl#再補充一點: 這種題目, 利用O#ed_op#SUB#ed_cl#1#ed_op#/SUB#ed_cl#O#ed_op#SUB#ed_cl#2#ed_op#/SUB#ed_cl#BA為梯形較好計算#ed_op#/DIV#ed_cl#

延長O1O2交AB於C
設O2C=1+a
(1+a)/1=(5+a)/3
a=1
∠PQB=60
PQ=√3cm

#ed_op#DIV#ed_cl#PQ = √3#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#(因為QA = QB = QP, 且AB = 2√3)#ed_op#/DIV#ed_cl#

#ed_op#DIV#ed_cl##ed_op#IMG alt="image file name: 2ke607c84e23.gif" src="http://yll.loxa.edu.tw/phpBB2/richedit/upload/2ke607c84e23.gif" border=0#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#半徑分別為3cm和1cm的☉#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#O1#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#，☉#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#O2#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#外切於#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#P#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#點，#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#AB#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#是一條外公切線，#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#A#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#、#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#B#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#是切點，#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#PQ#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#⊥#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#O1#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#O2#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#於#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#P#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#交#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#AB#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#於#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#Q，#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#求#ed_op#/SPAN#ed_cl##ed_op#SPAN lang=EN-US style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#PQ#ed_op#/SPAN#ed_cl##ed_op#SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 新細明體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 新細明體; mso-ansi-language: EN-US; mso-fareast-language: ZH-TW; mso-bidi-language: AR-SA"#ed_cl#的長。#ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#