Approximate √90 to the nearest hundredth

Well the answer for √90 is 9.486832980 and so on, but you only have to look at the first 4 decimal numbers since your looking for the thousandth so 9.4868. next you would look at the last number which is 8 and see if 8 is higher or lower than 5 and obviously it is so it would make 6 go a number up making it 7. so the new number is 9.487 which is your answer