Step 1:
The first step to converting 125421.7809663 to a fraction is to re-write 125421.7809663 in the form p/q where p and q are both positive integers. To start with, 125421.7809663 can be written as simply 125421.7809663/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 125421.7809663, which in this case is 7. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 125421.7809663/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 125421.7809663/1 each by 10000000:
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 125421.7809663 as a fraction:
501687/4 / 1