b)KÎ AH vu«ng gãc víi MN ( H ∈ MN ) . Do CM + CN =7 vµ CN- CM=1cm⇒ CN=
4cm; CM= 3cm, MN = 5 cmTa cã ∆AMN = ∆AIN ⇒ AH = AD ⇒ IN = MN∆AMH = ∆AID ⇒ ID = MH mµ ID = BM ⇒ MH = BMTa l¹i cã : DN + BM = MN = 5 vµ CM+MB = CN + ND ⇒ CN- CM = MB- ND=1⇒ DN =2cm; BM =3cm; BC = AD = AH = 6 cm-Tan AMH ==&[r]