Answer: what would the answer be?
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer: 10%
Step-by-step explanation:
The difference between his estimated and actual distance is 15 - 13.5 = 1.5
The percentage of error is the difference divided by the actual value.
1.5÷15 = 0.10
Converted to a percentage, it is 10%
 
        
                    
             
        
        
        
The answer would be 24pi inches. 
You can find this by using the formula for a circumference and plugging in the value of the radius. 
C = 2pi*r
C = 2pi * 12
C = 24pi