(2)∵AB=12,BC=16∴AC=√(12²+16²)=20,CO=1/2AC=10∵在△ABC和△COF中。∠ACB=∠FCO,∠ABC=∠FOC=90°∴△ACB∽△∠FCOFO/AB=CO/BCFO=CO/BC×AB=10/16×12=7.5EF=2FO=15