Chapter 1 - Foundations for Algebra - 1-3 Real Numbers and the Number Line - Practice and Problem-Solving Exercises - Page 20: 21

16

The problem asks us to estimate the square root to the nearest integer answer, so we consider the closest square root that gives us an integer answer. We know that the square root of 256 is 16. The square root of 242 is fairly close to the square root of 256, so 16 is a good approximation for the square root of 242. (Also, note that the square root of 225, 15, is not quite as close to the square root of 242 as the square root of 256 is, so 16 is a better approximation than 15.)