There's a 9 in the thousandths place. The next digit to the right is 1, which is not 5 or more. So we'll just drop that 1 and that's why the answer is 3.569
Rounding is the process of shortening a number to a certain number of digits by finding the closest number with the desired number of digits. When rounding, look one digit to the right of the desired decimal place. In this case, you want the thousandths place. The thousandths place is 3 digits after the decimal, so look at the number next to the 9, the 1. If the number is 5 or greater round up, if it is 4 or less round down. Therefore, 3.5691 should be rounded down to 3.569.
