\(5\widehat{xOy}=4\widehat{yOz}\Rightarrow\frac{\widehat{yOz}}{5}=\frac{\widehat{xOy}}{4}=\frac{\widehat{yOz}-\widehat{xOy}}{5-4}=\frac{10^0}{1}=10^0\)
\(\Rightarrow\widehat{yOz}=50^0;\widehat{xOy}=40^0\Rightarrow\widehat{yOz}+\widehat{xOy}=50^0+40^0=90^0\)
mà\(\widehat{yOz}+\widehat{xOy}=\widehat{xOz}\)(vì\(\widehat{xOy},\widehat{yOz}\)kề nhau) nên\(\widehat{xOz}=90^0\)=> Ox vuông góc Oz