Fatty acid converted to acetyl coa through a process called BETA OXIDATION.
{ beta oxidation is a process in which fatty acid molecules broken down to produce energy } specially it is used to convert long acetyl coa chain in to short progressively fatty acetyl coa chains . this reaction release acetyl coa , FADH2 , NADH three of which then enter other metabolic process called critic acid cycle , in which ATP is produce is used as energy