O.90985 to three significant digits

0.910

you need to round it up 0.90985 the 9 would be the 3rd significant digit so round it because the number after is higher than 5 so 0.910

To round a number to three significant digits, we need to look at the first three digits from the left.

In this case, the first three digits are 0.909.

The next digit after the third one is 8, which is greater than or equal to 5. According to the rounding rules, when the next digit is 5 or greater, we round up by increasing the last digit kept by 1.

So, rounding 0.90985 to three significant digits gives us 0.910.