Use the unit multipliers to go from feet to miles, from miles to km and from km to meters. This can be done all at once using dimensional analysis.

Next multiply all the numerators together. 2640 is part of the numerator expression
Numerators: 2640 * 1 * 1.6*1000 = 4224000
Denominators: 5280*1 * 1 = 5280
Now divide the numerators by the denominators
Numerator / denominator = 4224000 / 5280= 800
Answer: 2640 feet = 800 meters.