Step 1:
The first step to converting 13209.765731371 to a fraction is to re-write 13209.765731371 in the form p/q where p and q are both positive integers. To start with, 13209.765731371 can be written as simply 13209.765731371/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 13209.765731371, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 13209.765731371/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 13209.765731371/1 each by 1000000000:
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 13209.765731371 as a fraction:
171727/13 / 1