11小题,要过程,急急,我会采纳的
解:∵∠A ∠ABC ∠ACB=180∴∠ABC ∠ACB=180-∠A∵∠CBE=180-∠ABC,BD平分∠CBE∴∠CBD=∠CBE/2=(180-∠ABC)/2=90-∠ABC/2∵∠BCF=180-∠ACB,CD平分∠BCF∴∠BCD=∠BCF/2=(180-∠ACB)/2=90-∠ABC/2∴∠BDC=180-(CBD ∠BCD)=180-(90-∠ABC/2 90-∠ACB/2)=∠ABC/2 ∠ACB/2=(∠ABC ∠ACB)/2=(180-∠A)/2=90-∠A/2。
解:∵∠A ∠ABC ∠ACB=180∴∠ABC ∠ACB=180-∠A∵∠CBE=180-∠ABC,BD平分∠CBE∴∠CBD=∠CBE/2=(180-∠ABC)/2=90-∠ABC/2∵∠BCF=180-∠ACB,CD平分∠BCF∴∠BCD=∠BCF/2=(180-∠ACB)/2=90-∠ABC/2∴∠BDC=180-(CBD ∠BCD)=180-(90-∠ABC/2 90-∠ACB/2)=∠ABC/2 ∠ACB/2=(∠ABC ∠ACB)/2=(180-∠A)/2=90-∠A/2。
收起