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標題: F.3平行四邊形4題 [打印本頁]

作者: billyconan 時間: 09-12-12 12:42 PM 標題: F.3平行四邊形4題

唔係好識做

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圖片附件: Question 2.JPG (09-12-12 12:42 PM, 32.74 KB) / 下載次數 38
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圖片附件: Question 3.JPG (09-12-12 12:42 PM, 42.29 KB) / 下載次數 45
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圖片附件: Question 4.JPG (09-12-12 12:42 PM, 58.01 KB) / 下載次數 43
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作者: abcdefg111 時間: 09-12-12 08:45 PM

1)Let <BAD=a <=角
so, <DCB=a
triangle ADP~= triangle QCB (SAS)
Let <QBC=b
<ADP=b
so,<QBA=180-a-b
<PDB=180-a-b
so PDBQ is parallelogram
2)AB=CD
Let <DAB=<DCB=a
AEB~=DFC (SAS)
let <EBA=b then <FDC=b
Let <ABC=c so <ADC=c
<EBF=c-b=<EDF

作者: abcdefg111 時間: 09-12-12 08:57 PM

3)PO=OR (diag. of//gram)
so PO/2=XO
OR/2=OY
OY=XO
OQ=OS(diag. of//gram)
so XQYS is //gram
4)a)Let <ABC=z
so <ADC=z
<EBC=z-60
<ADF=z-60
AD=BC
BE=FD
EBC~=AFD(SAS)
b)since AFD~=BEC
AF=EC
FC=AE
so AEFC is //gram

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