Step 1:
The first step to converting 85439.867128424 to a fraction is to re-write 85439.867128424 in the form p/q where p and q are both positive integers. To start with, 85439.867128424 can be written as simply 85439.867128424/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 85439.867128424, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 85439.867128424/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 85439.867128424/1 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 85439.867128424 as a fraction:
598079/7 / 1