Step 1:
The first step to converting 81398.90983631 to a fraction is to re-write 81398.90983631 in the form p/q where p and q are both positive integers. To start with, 81398.90983631 can be written as simply 81398.90983631/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 81398.90983631, which in this case is 8. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 81398.90983631/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 81398.90983631/1 each by 100000000:
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 81398.90983631 as a fraction:
895388/11 / 1