Answer
WZ=1.75
Work Step by Step
The measure of an inscribed angle is equal to half of measure of the angle of the arc it inscribes. Thus, the measure of angle Z is 90 degrees. Since the measure of XO equals the measure of OY, we find that the measure of XY equals 10. Using the Pythagorean thorem, we obtain that YZ equals $\sqrt{10^2 - 6^2} = 8$. Since XW is congruent to WY, we find:
$6^2 + WZ^2 = (8 - WZ)^2 \\ 36 = 64 - 16WZ \\ WZ = 1.75$