The answer is 18 cm
Half of 72 is 36
Since YZ is 30, you would subtract 30 from 36 in order to get XY, so you would get 6 for XY
Half of circle W is 24, since it says the diameter of it is 48
So you would subtract XY from half of the diameter of W in order to get WX
It would look like this:
24-6=18
