* Your car's owner's manual: This is the most reliable source.
* The sticker on your driver's side doorjamb: This often lists tire size and sometimes the bolt pattern.
* The wheel itself: The bolt pattern is stamped on the back of the wheel.
* A reliable online parts database: Input your VIN (Vehicle Identification Number) into a reputable parts website (like RockAuto, etc.) to see what wheels fit your specific vehicle.
Without knowing your specific Cougar's configuration, I cannot give you the correct bolt pattern.