Step 1:
The first step to converting 3939.9543871439 to a fraction is to re-write 3939.9543871439 in the form p/q where p and q are both positive integers. To start with, 3939.9543871439 can be written as simply 3939.9543871439/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 3939.9543871439, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 3939.9543871439/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 3939.9543871439/1 each by 10000000000:
Step 3:
Now the last step is to simplify the fraction (if possible) by finding similar factors and cancelling them out, which leads to the following answer for 3939.9543871439 as a fraction:
82739/21 / 1