a) $Oy$ nằm giữa $Ox;Oz$ ( vì $\widehat{xOy}<\widehat{xOz}$)$\Rightarrow \widehat{yOz}=\widehat{xOz}-\widehat{xOy}=120-30=90$b) $\widehat{xOn}=\frac{\widehat{xOz}}{2}=\frac{120}{2}=60$ $\widehat{xOm}=\frac{\widehat{xOy}}{2}=\frac{30}{2}=15$ $Om$ nằm giữa $Ox;On$ ( vì $\widehat{xOm}<\widehat{xOn}$)$\widehat{mOn}=\widehat{xOn}-\widehat{xOm}=60-15=45$
a) $Oy$ nằm giữa $Ox;Oz$ ( vì $\widehat{xOy}<\widehat{xOz}$)$\Rightarrow \widehat{yOz}=\widehat{xOz}-\widehat{xOy}=120-30=90$b) $\widehat{mOn}=\widehat{xOn}-\widehat{xOm}=\frac{\widehat{xOz}-\widehat{xOy}}{2}=\frac{120-30}{2}=45$
a) $Oy$ nằm giữa $Ox;Oz$ ( vì $\widehat{xOy}<\widehat{xOz}$)$\Rightarrow \widehat{yOz}=\widehat{xOz}-\widehat{xOy}=120-30=90$b) $\widehat{
xOn}=\
frac{\widehat{xO
z}}{2}=\frac{120}
{2}=60$ $\widehat{xOm}=\frac{\widehat{xO
y}}{2}
=\frac{30}{2}=15$ $Om$ nằm giữa $Ox;On$ ( vì $\widehat{xO
m}
<\widehat{xOn}
$)$\widehat{
mOn}=\
wideha
t{
xOn}
-\widehat{
xOm}
=60-15=45$