Step 1:
The first step to converting 4139.9402657468 to a fraction is to re-write 4139.9402657468 in the form p/q where p and q are both positive integers. To start with, 4139.9402657468 can be written as simply 4139.9402657468/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 4139.9402657468, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 4139.9402657468/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 4139.9402657468/1 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 4139.9402657468 as a fraction:
66239/16 / 1