The answer you are looking for is 25.
2500 / 10² = 25
Since the formula for finding the volume is 
V = Pi r² h
        
                    
             
        
        
        
Answer:
B 
Step-by-step explanation:
The two triangles are congruent because they have three rispective side congruent 
AB and AD are both radiuses and AC is in common 
so m arc BC is 78 degrees 
 
        
             
        
        
        
The mean of the answer is 20.5 because you add all of the number together and divide by 6 because there's 6 numbers. 
I'm sorry, but I don't know how to do the standard deviation... 
Hope this helped!