a) Oy nằm giữa Ox;Oz ( vì $\widehat{xOy}>\widehat{xOz})\Rightarrow \widehat{yOz}=\widehat{xOz}-\widehat{xOy}=120-30=90b) \widehat{mOn}=\frac{\widehat{xOz}-\widehat{xOy}}{2}=\frac{120-30}{2}=45$
a)
Oy nằm giữa
Ox;Oz ( vì $\widehat{xOy}&
lt;\widehat{xOz}
)\Rightarrow \widehat{yOz}=\widehat{xOz}-\widehat{xOy}=120-30=90
b) \widehat{mOn}=\frac{\widehat{xOz}-\widehat{xOy}}{2}=\frac{120-30}{2}=45$