赏月阁
幼苗
共回答了18个问题采纳率:94.4% 举报
∠BPC=90-∠A/2
∵∠DBC=180-∠ABC,BP平分∠CBD
∴∠PBC=∠CBD/2=(180-∠ABC)/2=90-∠ABC/2
∵∠BCE=180-∠ACB,CP平分∠BCE
∴∠PCB=∠BCE/2=(180-∠ACB)/2=90-∠ACB/2
∴∠BPC=180-(∠PBC+∠PCB)
=180-(90-∠ABC/2+90-∠ACB/2)
=(∠ABC+∠ACB)/2
=(180-∠A)/2
=90-∠A/2
1年前
6