Step 1:
The first step to converting 13172.511945398 to a fraction is to re-write 13172.511945398 in the form p/q where p and q are both positive integers. To start with, 13172.511945398 can be written as simply 13172.511945398/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 13172.511945398, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 13172.511945398/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 13172.511945398/1 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 13172.511945398 as a fraction:
26345/2 / 1