Identify fifth decimal place: Identify the fifth decimal place in the number 78.153598796 to determine if the fourth decimal place should be rounded up or stay the same.The fifth decimal place is 9, which is greater than 5. Therefore, the fourth decimal place (8) will be rounded up by 1.
Round to four decimal places: Round the number to four decimal places by increasing the 4th decimal place by 1 and removing the rest of the decimal places.78.153598796 rounded to four decimal places is 78.1536 because the 5th decimal place (9) causes the 4th decimal place (8) to round up to 9.