来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/08/19 06:53:59
求12题的解!
![](http://img.wesiedu.com/upload/0/fb/0fbfc285d74066efd45593c1d7ddab93.jpg)
设AB边到C的高为h1,BC边到A的高为h2,
S⊿ABC=6,AD=2BD,
S⊿ADC/S⊿DBC=(AD*h1/2)/(BD*h1/2)=AD/BD=2
S⊿ABC=S⊿ADC+S⊿DBC,
可得出:S⊿ADC=4,S⊿ABD=2,
同理:S⊿ABE=S⊿ACE=3
S1-S2=S⊿ADF-S⊿CEF
=S⊿ADF+S⊿AFC-S⊿AFC-S⊿CEF
=(S⊿ADF+S⊿AFC)-(S⊿AFC+S⊿CEF)
=S⊿ADC-S⊿AEC
=4-3=1