Given, the area of a square, A=225 square units.
The equation of the area of a square is,
[tex]A=a^2[/tex]Here, a is the length of a side of the square.
Put A=225 in the above equation and find a.
[tex]\begin{gathered} 225=a^2 \\ \sqrt[]{225}=a \\ 15=a \end{gathered}[/tex]Therefore, the length of a side of the square is 15 units.
