## Elementary Geometry for College Students (6th Edition)

$XZ=8$
$\triangle RST$ is a 45-45-90 Triangle. The length of the hypotenuse is $(leg length)\sqrt 2$. Since the hypotenuse is $8 \sqrt2$, then the length of each leg equals $8$. So... $XZ=ZY=8$ or just $XZ=8$