Answer:
I think it might be 30pi m or 94.2 m. 
Step-by-step explanation: So you are finding the perimeter of the circle. You have a radius of 15, the perimeter for a circle is C=2pir. Now we can do  C=2pi(15). The answer is 30pi or C=2 x 3.14 x 15= 94.2 Hope this helps. 
 
        
             
        
        
        
The ratio would be 3:4, or however you write ratios.
Hope this helped! :)
 
        
                    
             
        
        
        
409,200,000,000= 4.092 × 10^11
        
                    
             
        
        
        
Answer:
advantage: it uses memory very efficiently than linear data structures 
disadvantages: Non - linear data structures are quite hard to understand and implement than linear data structures 
 
        
             
        
        
        
The answer is A linear positive association