解:AN=2NC,则AN/AC=2/3.过点N作BC的平行线,交AM于D.则:⊿AND∽⊿ACM,DN/MC=AN/AC=2/3;∵BM=MC.∴DN/BM=DN/MC=2/3, BM/DN=3/2.∴BP/PN=BM/DN=3/2, BP=(3/2)PN.故m的值为3/2.
补充条件
4:1
