Step 1:
The first step to converting 19897.91421088 to a fraction is to re-write 19897.91421088 in the form p/q where p and q are both positive integers. To start with, 19897.91421088 can be written as simply 19897.91421088/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 19897.91421088, which in this case is 8. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 19897.91421088/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 19897.91421088/1 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 19897.91421088 as a fraction:
218877/11 / 1