Step 1:
The first step to converting 720.9045569961 to a fraction is to re-write 720.9045569961 in the form p/q where p and q are both positive integers. To start with, 720.9045569961 can be written as simply 720.9045569961/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 720.9045569961, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 720.9045569961/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 720.9045569961/1 each by 10000000000:
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 720.9045569961 as a fraction:
15139/21 / 1