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huong3498


cho tam giac ABC can tai A, qua B ve duong thang vuong goc voi BC cat AC keo dai tai D
a) chung minh A la trung diem cua CD
b) ke duong cao BE cua tam giac ABC, qua C ve duong thang song song voi BE, cat AB keo dai tai F. Chung minh rang AB^2=AE.AF
a) chung minh A la trung diem cua CD
b) ke duong cao BE cua tam giac ABC, qua C ve duong thang song song voi BE, cat AB keo dai tai F. Chung minh rang AB^2=AE.AF