Step 1:
The first step to converting 81580.9431521 to a fraction is to re-write 81580.9431521 in the form p/q where p and q are both positive integers. To start with, 81580.9431521 can be written as simply 81580.9431521/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 81580.9431521, which in this case is 7. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 81580.9431521/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 81580.9431521/1 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 81580.9431521 as a fraction:
81581/1 / 1