Giải
Cách 1:
\(\left\{{}\begin{matrix}a//b\\a\perp d\end{matrix}\right.\Rightarrow b\perp d\)
Ta có: \(\left\{{}\begin{matrix}d\cap a=\left\{A\right\}\\d\cap c=\left\{C\right\}\end{matrix}\right.\)
Và \(\widehat{F}=\widehat{E}=35^0\) ( sole ngoài )
\(\Rightarrow b//c\)
Cách 2:
Biết: \(\left\{{}\begin{matrix}a//b\\a\perp d\end{matrix}\right.\Rightarrow b\perp d\)
Ta có: \(\widehat{F}=\widehat{D}=35^0\)( sole ngoài )
\(\Rightarrow a//c\)
Ta lại có:\(\left\{{}\begin{matrix}a//b\\a\perp d\\b\perp d\\a//c\end{matrix}\right.\Rightarrow b//c\)