Cho tam giac ABC can tai A co AB= 4 cm, BC= 5cm. Tren tia AC lay diem D sao cho \(\widehat{ABD}\)=\(\widehat{ACB}\); KE AE vuong goc BD ( E thuoc BD)
1; Tinh AC
2. So sanh: \(\widehat{ABC}\) va \(\widehat{ACB}\): AC va AD
3. Chung minh AE di qua trung diem cua BC
4. KE duong trung tuyen BM cua tam giacABC cat AE tai G. Tinh AG