Bai 1: Cho \(\widehat{xoy}\)=120. Ve tia phan giac Ot. Tinh \(\widehat{toy}\).
Bai 2: Ve 4 tia chung goc Ax, Ay, Az, At sao cho Ax va Ay doi nhau, 2 tia Az va At nam tren nua mat phang doi nhau co bo chung xy.
a, Tia At nam giua 2 tia nao?
b, Ke ten cac goc ke bu co tren hinh,