... Khdi bat dien diu thudc loai nao thuoc loai {6, 12 1 cac loai tii:dien {n, p] G V cho HS d i l n vao bang tdm tat sau: Loai 13 ,3} {4,3} (3,4} 15 ,3) 13 ,5) 40 Ten goi ~ So dinh So canh So mat HOATPONG ... GV cho HS dgc va suy nghT tra loi cac cau hdi sau : H 11 Mat ciia khdi da dien la gi ? HI2 Neu khai niem dinh va canh ciia khdi da dien 11 13 Dilm thuoc mat ciia khdi da dien cd la dilm ciia khdi ... tilt nhu SGK • GV neu he qua 1: Hai tir dien deu cd cgnh bdng ihi bdng HI8 Chiing minh he qua • GV neu he qua 2: 25 Uai hinh lap phucrng co canh hdng thi hdng 11 19 Chiing minh he qua HOATDONC...