Step 1:
The first step to converting 400489.56639831 to a fraction is to re-write 400489.56639831 in the form p/q where p and q are both positive integers. To start with, 400489.56639831 can be written as simply 400489.56639831/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 400489.56639831, which in this case is 8. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 400489.56639831/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 400489.56639831/1 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 400489.56639831 as a fraction:
800979/2 / 1