Step 1:
The first step to converting 72172.921406168 to a fraction is to re-write 72172.921406168 in the form p/q where p and q are both positive integers. To start with, 72172.921406168 can be written as simply 72172.921406168/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 72172.921406168, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 72172.921406168/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 72172.921406168/1 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 72172.921406168 as a fraction:
866075/12 / 1