Step-by-step explanation:B
 
        
                    
             
        
        
        
The answer is C. 
You need you use Pythagoras theorem 2 times to have 2 equations with the same sides i.e. for example a2 + b2 = 81 and a2 - b2 = 9. 
You can do it as you have different triangles but with the same sides. 
 
        
             
        
        
        
Answer:
6400
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer: 78 square units
Step-by-step explanation:
 
        
             
        
        
        
Answer:
???
Step-by-step explanation:
This is VERY confusing. Seems like it's already answered there.