Find the thousandths place then look at the number to the right of it. If it is 5 or higher the thousandths place rounds up to the next higher number. If it's 4 or less then it rounds down and the thousandths place stays the same.
75.4614
Thousandths place is the 1. The number to the right is 4 so the thousandths place rounds down and so it stays the same. Everything to the right of the thousandths place becomes zero so you don't even have to write it. Your answer is
75.461