d' //d''\Rightarrow \widehat{E_1}=\widehat{C}=60 (slt);\widehat{G_2}=\widehat{BDd'}=110(đv)\widehat{G_2}+\widehat{G_3}=180 (kề bù ) \Rightarrow \widehat{G_3}=180-\widehat{G_2}=180-110=70
d'//d''\Rightarrow \widehat{D_4}=\widehat{G_2}=110(slt)
d//d''\Rightarrow \widehat{E_1} = \widehat{A_5}=60(đv); \widehat{B_6}=\widehat{G_3}=70(đv)