the Given:
The side of the square is a = 10 inches.
Explanation:
The length of the diagonal of the square is determined by Pythagoras theorem.
[tex]\begin{gathered} d=\sqrt[]{a^2+a^2} \\ =\sqrt[]{2a^2} \\ =\sqrt[]{2}a \end{gathered}[/tex]Substitute 10 for a in the equation to determine the length of the diagonal of the square.
[tex]\begin{gathered} d=\sqrt[]{2}\cdot10 \\ =10\sqrt[]{2} \end{gathered}[/tex]So the answer is,
[tex]10\sqrt[]{2}[/tex]