So to find the answer, first we need to understand how to approximate square roots. 80 is an imperfect square, so we're going to have to round the answer. To find that, we need to find the multiples 80.
72, 80, 81. 8, x, 9
So the distance apart between 72 and 81 is 9. The answer, x, is obviously between 8 and 9, and since the distance between these to is 9, your answer is going to be 8.9 .
