The area of a square is given by the next formula:
[tex]A_s=s\cdot s[/tex]A square has all the sides with an equal measure.
Therefore, all the sides for this square have a measure of 5d.
Replace these values on the area formula:
[tex]A_s=(5d)(5d)[/tex]Therefore, the area for the square is:
[tex]A_s=25d^2[/tex]