A diesel engine does not use spark plugs to ignite the fuel and air in the cylinders. Instead, the temperature required to ignite the fuel occurs because the pistons compress the air in the cylinders. Suppose that air at an initial temperature of 21 degrees C is compressed adiabatically to a temperature of 688 degrees C. Assume the air to be an ideal gas for which gamma = 7/5. Find the compression ratio, which is the ratio of the initial volume to final volume.