Step 1:
The first step to converting 86399.621562365 to a fraction is to re-write 86399.621562365 in the form p/q where p and q are both positive integers. To start with, 86399.621562365 can be written as simply 86399.621562365/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 86399.621562365, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 86399.621562365/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 86399.621562365/1 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 86399.621562365 as a fraction:
259199/3 / 1