a) Ta có: \(\widehat{xOy}+\widehat{yOz}=180^0\)(hai góc kề bù)
⇔\(\widehat{yOz}=180^0-\widehat{xOy}=180^0-50^0=130^0\)
Vậy: \(\widehat{yOz}=130^0\)
b) Ta có: \(\widehat{yOt}=\widehat{zOt}=\frac{\widehat{yOz}}{2}\)(Ot là tia phân giác của \(\widehat{yOz}\))
hay \(\widehat{tOz}=\frac{130^0}{2}=65^0\)
⇒\(\widehat{tOz}>\widehat{xOy}\left(65^0>50^0\right)\)