已知线段AB,在AB的延长线上取一点C,使BC=3AB,在BA的延长线上取一点D,使DA=3/2AB,E是DB中点,且EB=40cm,求DC的长

|------------|---|----------|--------------------------|D E A B C设：AB=x,则：DA=(3/2)x、BC=3x则：DB=DA＋AB=(3/2)x＋x=(5/2)x=2EB=80得：x=32则：DC=DB＋BC=80＋3x=80＋96=176cm