DF交△ABC的AB于D,交BC于E,交AC延长线F,∠ABC和∠ADF平分线交G,∠ACB和∠AFD平分线交H,证:∠
1个回答

∠G=1/2∠ADF-1/2∠ABC

∠H=1/2∠ACB-1/2∠AFD

∠G=∠H 1/2∠ADF-1/2∠ABC=1/2∠ACB-1/2∠AFD

∠ADF-∠ABC=∠ACB-∠AFD

∠ADF+∠AFD=∠ABC+∠ACB

这两边都等于180°-∠A

得证.

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