Whats the distance from point y to qx in the figure

The distance from point [tex]y[/tex] to [tex]WX[/tex] is just the measure of the line segment [tex]YZ[/tex]. Notice that [tex]YZ[/tex] is one of the sides of the right triangle [tex]XYZ[/tex], so to find its length we are going to use the Pythagorean theorem:
[tex](YZ)^2=(XY)^2-(XZ)^2[/tex]
[tex](YZ)^2=(10 \sqrt{2} )^2-10^2[/tex]
[tex](YZ)^2=200-100[/tex]
[tex](YZ)^2=100[/tex]
[tex]YZ= \sqrt{100} [/tex]
[tex]YZ=10[/tex]

We can conclude that the correct answer is B. 10