Step 1:
The first step to converting 3971.8985371807 to a fraction is to re-write 3971.8985371807 in the form p/q where p and q are both positive integers. To start with, 3971.8985371807 can be written as simply 3971.8985371807/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 3971.8985371807, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 3971.8985371807/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 3971.8985371807/1 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 3971.8985371807 as a fraction:
39719/10 / 1