Step 1:
The first step to converting 76.420429686816 to a fraction is to re-write 76.420429686816 in the form p/q where p and q are both positive integers. To start with, 76.420429686816 can be written as simply 76.420429686816/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 76.420429686816, which in this case is 12. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 76.420429686816/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 76.420429686816/1 each by 1000000000000:
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 76.420429686816 as a fraction:
6725/88 / 1