Formula for finding mean:
Mean = (a1 + a2 + ... + an) / n
Mean is another word for  average; average number of a data set.
Problems with steps:
---------------------------------------------------------------------------------------
1) 9, 3, 6
Average =  Sum/Count
Sum =   18/6
Count = 3
2) 14, 12, 17, 9
52/4
Mean = 13
3) 15,8,10,5,7
= 45/5
Mean = 9
4) 18,19,11
= 48/3
Mean = 16
5) 4,20,16,4
= 44/4
Mean = 11
6) 12,11,12,20,15
= 70/5
Mean= 14
7) 19,8,3
= 30/3
Mean = 10
8) 7,13,6,2
= 28/4
Mean = 7
9) 12,15,17,2,14
60/5
Mean = 12
10) 10,18,8
= 36/3
Mean = 12
11) 5,2 ,0,1
= 8/4 
= 2
12) 3,9,5,16,7
= 40/5
Mean = 8
SOLVED !
Hope this helps!
- ROR
 
        
             
        
        
        
Answer:
8 . 76209992276
Step-by-step explanation:
does this help
 
        
             
        
        
        
Divide the area of the banner by 4 and the perimeter by 4 as well P=39 A=374
        
             
        
        
        
Answer:
33.4933333333, rounded, 
4/3x3.14x2x2x2=33.4933333333