Answer:
Side-angle-side postulate
Step-by-step explanation:
First, you know that angle XZW = YZW because they are both 90 degrees.
Next, you know that side WZ = side WZ because of the reflexive property (they are the same side)
Lastly, you know that YZ = XZ because Z is the midpoint meaning it divides the entire thing perfectly in half
You have two sides and the included angle, so it is SAS.
