a. Ta có: \(\widehat{xOv}+\widehat{yOv}=\widehat{xOy}\)
\(=>\widehat{xOv}=\widehat{xOy}-\widehat{yOv}\)
\(=>\widehat{xOv}=\widehat{xOy}-90^0\) 1
\(\widehat{tOy}+\widehat{xOt}=\widehat{xOy}\)
\(\widehat{tOy}=\widehat{xOy}-\widehat{xOt}\)
\(\widehat{tOy}=\widehat{xOy}-90^0\) 2
Từ 1,2 => \(\widehat{xOv}=\widehat{yOt}\)
b.
Vì Om là tia pg của \(\widehat{xOy}\) \(=>\widehat{xOm}=\widehat{yOm}\)
\(=>\widehat{xOv}+\widehat{vOm}=\widehat{yOt}+\widehat{tOm}\)
Vì \(\widehat{xOv}=\widehat{yOt}\)
\(=>\widehat{vOm}=\widehat{tOm}\)
\(=>Om\) là tia pg của góc \(\widehat{tOv}\)