Step 1:
The first step to converting 641673509.72406 to a fraction is to re-write 641673509.72406 in the form p/q where p and q are both positive integers. To start with, 641673509.72406 can be written as simply 641673509.72406/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 641673509.72406, which in this case is 5. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 641673509.72406/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 641673509.72406/1 each by 100000:
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 641673509.72406 as a fraction:
641673509/1 / 1