cho tam giac ABC vuong o A co AB=15cm va AC=12cm duong trung tuyen AM
Tinh BC va AM
Ve Ax vuong goc AM va By vuong goc BA.Tia Ax va By cat nhau tai E.Ve BF vuong goc AE tai F.CM :goc ABF =gocBAMva ΔABCΔABC dong dang ΔFBEΔFBE
AM∩BE={D},MF∩BE={I}.CM:ABClaHCNAM∩BE={D},ME∩BF={I}.CM:ABClaHCN,I la trung diem cua BF
ME∩AB={K}.ME∩AB={K}.CM: D,F,K thẳng hàng