Step 1:
The first step to converting 777.820721638 to a fraction is to re-write 777.820721638 in the form p/q where p and q are both positive integers. To start with, 777.820721638 can be written as simply 777.820721638/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 777.820721638, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 777.820721638/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 777.820721638/1 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 777.820721638 as a fraction:
21779/28 / 1