Which represents a side length of a square that has an area of 450 square inches?

I have been a high school/jr high math teacher for the past 13 years. I am happy to explain how to proceed with this problem.
A square is a figure where ALL sides are exactly the same. The find the area of the square you would multiply one side times another side. You would be multiplying a number times itself. So if you already have the area, you would take the square root to find your answer. When you do, you end up with 21.21 square inches rounded to the nearest hundredth.