We know the length of base and the perpendicular side, so using the Pythagorean identity, we can find the length of hypotenuse.
[tex] h^{2} = (9 \sqrt{2})^{2} + (9 \sqrt{2})^{2} \\ \\
h^{2}=162+162 \\ \\
h^{2}=324 \\ \\
h= \sqrt{324} \\ \\
h=18 [/tex]
Thus, the length of the hypotenuse will be 18.
