Asquare patio has an area of 200 square feet. how long is each side of the patio to the nearest 0.05?

Squares are equal on all sides, and you find the area by multiplying the length times the width, so can assume that the length and width are the same. 
That means by finding the square root (a number that equals another number when multiplied by itself) of 200, you should get your answer.
200 isn't a perfect square so you're going to get a decimal, which is why the square root of 200 is 14.14213562
By rounding up to the nearest 0.05, you'll end up with 14.14, which is the answer.

All you have to do is multiply