I
innocent_baby
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
Bai 1:
Cho tam giác ABC (AB<AC) nội tiếp (O;R) có đuong kính AK.Goi H la giao diêm cua 3 duong cao AD:BE:CF cua tam giac ABC.M la trung diem cua BC.
1,CMR:AB.AC=2R.AD
2/CMR:Tu giac EFDM noi tiep.
3/CMR:OC vuong goc voi DE.
Bai 2:cho (O:R) co duong kinh AB vuong goc voi day cung MN tai H(H nam giua O va B).Tren tia MN lay diem C nam ngoai (O) sao cho AC cat (O,R) tai K khac A,2 day MN va BK cat nhau tai E.
1/CMR:tu giac AHEK noi tiep.va tam giac CAE dong dang voi tam giac CHK.
2/Qua N ke duong thang vuong goc voi AC cat MK tai F.CMR:tam giac NFK can.
3/gia su:KE=KC.CMR:OK song song voi MN .Khi B dich chuyen tren (O:R) thi C dich chuyen tren duong nao?
Cho tam giác ABC (AB<AC) nội tiếp (O;R) có đuong kính AK.Goi H la giao diêm cua 3 duong cao AD:BE:CF cua tam giac ABC.M la trung diem cua BC.
1,CMR:AB.AC=2R.AD
2/CMR:Tu giac EFDM noi tiep.
3/CMR:OC vuong goc voi DE.
Bai 2:cho (O:R) co duong kinh AB vuong goc voi day cung MN tai H(H nam giua O va B).Tren tia MN lay diem C nam ngoai (O) sao cho AC cat (O,R) tai K khac A,2 day MN va BK cat nhau tai E.
1/CMR:tu giac AHEK noi tiep.va tam giac CAE dong dang voi tam giac CHK.
2/Qua N ke duong thang vuong goc voi AC cat MK tai F.CMR:tam giac NFK can.
3/gia su:KE=KC.CMR:OK song song voi MN .Khi B dich chuyen tren (O:R) thi C dich chuyen tren duong nao?