Step 1:
The first step to converting 1158.9979512459 to a fraction is to re-write 1158.9979512459 in the form p/q where p and q are both positive integers. To start with, 1158.9979512459 can be written as simply 1158.9979512459/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 1158.9979512459, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 1158.9979512459/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 1158.9979512459/1 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 1158.9979512459 as a fraction:
565591/488 / 1