Answer
$(15\sqrt{2}) \text{ } in$
Work Step by Step
Using $a^2+b^2=c^2$ (or the Pythagorean Theorem), then
\begin{array}{l}\require{cancel}
x^2+x^2=30^2
\\\\
2x^2=900
\\\\
x^2=\dfrac{900}{2}
\\\\
x^2=450
\\\\
x=\sqrt{450}
\\\\
x=\sqrt{225\cdot2}
\\\\
x=\sqrt{(15)^2\cdot2}
\\\\
x=15\sqrt{2}
.\end{array}
Hence, the sides measure $
(15\sqrt{2}) \text{ } in
.$