Question

 tìm x

Answer 1

\(HOI=DOE=180^0-\left(30^0+45^0\right)=105^0\left(doidinh\right)\)

\(\Rightarrow x=180^0-\left(105^0+40^0\right)=35^0\left(tong3goctrong1tg\right)\)

Answer 2

Xét ΔHOI có:\(\widehat{H}+\widehat{HOI}+\widehat{I}=180^o\Rightarrow\widehat{HOI}+30^o+45^o=180^o\Rightarrow\widehat{HOI}=105^o\)

Ta có: \(\widehat{HOI}=\widehat{DOE}=105^o\left(2.góc.đối.đỉnh\right)\)

Xét ΔDOE có:\(\widehat{D}+\widehat{DOE}+\widehat{E}=180^o\Rightarrow x+40^o+105^o=180^o\Rightarrow\widehat{HOI}=35^o\)

Answer 3