$\widehat{xOy}$ = $\widehat{x'Oy'} = 62^o$ (2 góc đối đỉnh)
$\widehat{xOy}$ + $\widehat{x'Oy} = 180^o$ (2 góc kề bù)
`=> 62^o` + $\widehat{x'Oy} = 180^o$
`=>` + $\widehat{x'Oy} = 118^o$
$\widehat{x'Oy}$ = $\widehat{xOy'} = 118^o$ (2 góc đối đỉnh)
*Vậy $\widehat{xOy}$ = $\widehat{x'Oy'} = 62^o$
$\widehat{x'Oy}$ = $\widehat{xOy'} = 118^o$