Giải thích các bước giải:
a)$\widehat{xOm}=\widehat{mOy}=\frac{\widehat{xOy}}{2}=\frac{60}{2}=30^{\circ}$
b)$\widehat{yOz}=180^{\circ}-\widehat{xOy}=180-60=120^{\circ}$
⇒$\widehat{yOn}=\widehat{zOn}=\frac{\widehat{yOz}}{2}=\frac{120}{2}=60^{\circ}$
Ta thấy: $\widehat{xOm}<\widehat{zOn} (30<60)$
c)$\widehat{mOn}=\widehat{mOy}+\widehat{yOn}$
=$30+60=90^{\circ}$
⇒$\widehat{mOn}$ là góc vuông