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標題:
maths~~~~~
發問:
As follows: 圖片參考：http://e.imagehost.org/0789/ScreenHunter_02_Mar_03_23_47.gif http://e.imagehost.org/0789/ScreenHunter_02_Mar_03_23_47.gif
最佳解答:
∠DCB + ∠GCB = 180° (同側鄰角) .... (1) ∠ABC + ∠GBC = 180° (同側鄰角) .... (2) BC = GB (同圓半徑) ∠GCB = ∠GBC (等腰ΔGCB 底角) 比較 (1) 和 (2): ∠DCB = ∠ABC (公理) 但 ∠DCB + ∠DAB = 180° (圓內接四邊形內對角) ∠ABC + ∠DAB = 180° (代入) 所以 AD // BC (同側內角互補)
其他解答:
maths~~~~~
發問:
As follows: 圖片參考：http://e.imagehost.org/0789/ScreenHunter_02_Mar_03_23_47.gif http://e.imagehost.org/0789/ScreenHunter_02_Mar_03_23_47.gif
最佳解答:
∠DCB + ∠GCB = 180° (同側鄰角) .... (1) ∠ABC + ∠GBC = 180° (同側鄰角) .... (2) BC = GB (同圓半徑) ∠GCB = ∠GBC (等腰ΔGCB 底角) 比較 (1) 和 (2): ∠DCB = ∠ABC (公理) 但 ∠DCB + ∠DAB = 180° (圓內接四邊形內對角) ∠ABC + ∠DAB = 180° (代入) 所以 AD // BC (同側內角互補)
其他解答:
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