So you know that the sum of angles in a triangle is 180°. 
You know two of the angles in triangle WXZ. The two angles are angle WXZ, which is 50° and angle XWZ, which is 90°. 
Now you can calculate angle WZX, by: 
180-50-90=40°.
        
                    
             
        
        
        
Answer:
The width of the frame is equal to  
  
Step-by-step explanation:
Let
x-------> the width of the frame picture
we know that
 
     

 
   
Simplify

The formula to solve a quadratic equation of the form  is equal to
 is equal to
 
in this problem we have

so
 
substitute in the formula
 
 
 
 ----> this solution is not logic
  ----> this solution is not logic
 
  
The width of the frame is equal to  
  
 
        
             
        
        
        
The answer is A. A^2+b^2=c^2