Question

Answer 1

Bài 2

a, Ta có OE là tia phân giác xOy

OF là tia phân giác yOz

\(\widehat{yOE}=\widehat{xOE}=\dfrac{1}{2}\widehat{xOy}\\ \widehat{yOF}=\widehat{zOF}=\dfrac{1}{2}\widehat{yOz}\)

\(\widehat{EOy}+\widehat{yOF}=\widehat{EOF}\\ \dfrac{1}{2}\widehat{xOy}+\dfrac{1}{2}\widehat{yOz}=\widehat{EOF}\\ \dfrac{1}{2}\left(xOy+yOz\right)=EOF\\ \dfrac{1}{2}.180=\widehat{EOF}\\ =>\widehat{EOF}=90\\ =>EO\perp OF\)