I am going to take a picture of the question

Determine the distance between point A and intersecting points of diagonal.
[tex]\begin{gathered} d=\sqrt[]{(2-5)^2+(3-1)^2} \\ =\sqrt[]{9+4} \\ =\sqrt[]{13} \\ =3.605 \end{gathered}[/tex]The diagona of square bisects each other and are equal in length. So
[tex]BD=2\cdot d[/tex]Determine the length of diagonal BD.
[tex]\begin{gathered} BD=2\cdot3.605 \\ =7.211 \\ \approx7.2 \end{gathered}[/tex]So length of diagnal BD is equal to 7.2.