What are the answer choices
        
             
        
        
        
I think it’s the second option
        
                    
             
        
        
        
Answer:
The correct option is D.
Step-by-step explanation:
We have to find the expresses this statement: A quantity x is equal to the sum of the squares of a and b.
The square of a can be written as a² and the square of b can be written as b².
The sum of squares of a and b can be written as

Since the quantity x is equal to the sum of the squares of a and b, therefore

Therefore option D is correct.
 
        
             
        
        
        
Angles in a triangle adds up to 180 
180 - (25.5 +120.2) = 34.3
So, missing angle is 34.3 degrees
Hope this helps!