Step 1:
The first step to converting 4291640.8591866 to a fraction is to re-write 4291640.8591866 in the form p/q where p and q are both positive integers. To start with, 4291640.8591866 can be written as simply 4291640.8591866/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 4291640.8591866, which in this case is 7. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 4291640.8591866/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 4291640.8591866/1 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 4291640.8591866 as a fraction:
4291640/1 / 1