1.tren cung 1 nua mat phang bo chua tia Ox,ve cac tia Oy va Oz sao cho \(\widehat{xOy}\)=30,\(\widehat{xOz}\)=60
a,tinh so do \(\widehat{yOz}\)=?
b,ve tia Ot la tia doi cua tia Ox.tinh so do \(\widehat{tOz}\)=?
c,ve tia Om la tia phan giac cua \(\widehat{tOz}\).chung to rang tia Oz la tia phan giac cua \(\widehat{xOm}\)
khong can ve hinh ,khong can lam cua a.lam cau b,c