证明题过程,
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证明题过程,
∵BD平分∠ABC,CD平分∠ACB
∴∠DBC=1/2∠ABC,∠DCB=1/2∠ACB
∵∠ABC+∠ACB=180°-∠A
∴∠DBC+∠DCB=1/2(180°-∠A)=90°-1/2∠A
∴∠BDC=180°-(90°-1/2∠A)
=90°+1/2∠A
证明题过程,
∵BD平分∠ABC,CD平分∠ACB
∴∠DBC=1/2∠ABC,∠DCB=1/2∠ACB
∵∠ABC+∠ACB=180°-∠A
∴∠DBC+∠DCB=1/2(180°-∠A)=90°-1/2∠A
∴∠BDC=180°-(90°-1/2∠A)
=90°+1/2∠A