This problem gives you the area of a square, and asks for the length of a side. The formula for the area
of a square, knowing the side
, is
![A = s^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/thwajl8nsw13oh3jl1iznf7u07fryox7xu.png)
But we are in the opposite situation: we know the area and we are looking for the side. So, we need to invert the formula above:
![s = \pm√(A)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/zv2ek4sivumpvffbgfidu5dcr2wav9jhno.png)
But since the length of a side can't be negative, we choose
![s = √(A)](https://img.qammunity.org/2019/formulas/mathematics/high-school/kw0uy17ad0mmas9ve4myrz53ot0culh4gv.png)
So, if we plug the value for the area, we have
![s = √(20.25) = 4.5](https://img.qammunity.org/2019/formulas/mathematics/middle-school/dbsgg0wuwhtujvb38i9tcmvwuufil0906z.png)