Geometry - Help

In a right triangle the median has the same length as half the hypotenuse because of the circumcircle of the triangle. Therefore:

$\triangle{ZCA}$ is isoceles and $\angle{ZAC}=\angle{ZCA}=90-\angle{ABX}$

$\angle{ABX}=90-\angle{BAX}=90-(\frac{\angle{BAC}}{2}-\angle{XAY})=90-(45-22)=67$

Thus $\angle{ZAC}=\angle{ZCA}=90-67=\boxed{23}$