So if we think of a test tube, it looks sort of like a cylinder. This means that its cross-section would be a circle. To find out how many turns a piece of thread would make around the test tube, we need to find the circumference of the test tube, then divide the length of the string by the circumference.
Step 1) Find the circumference
C = pi x diameter
C = 3.14 x 3
C = 9.42
Step 2) Divide the length of the string by the circumference
90.42 / 9.42 = 9.5987
The string would make approximately 9.60 turns around the test tube.
Hope this helps!! :)
 
        
             
        
        
        
Note: You missed to add the dot plots chart. As I found the chart after a little research. Thus, I am attaching it and based on that dot plot chart I am solving the question which anyways would clear you concept.
Answer:
'There are about 2 more students in each class at Oak Middle School than at Poplar Middle School' is the correct statement.
Step-by-step explanation:
From the diagram, it is clear that
The data set containing Poplar Middle School:
20   20   20   21   21   21   21   21   22   22   22   22   22   22   22   23   23   23   23   24   
The mean of a data set is the sum of the terms divided by the total number of terms. Using math notation we have:

   
    
The data set containing Oak Middle School:
20   21   21   22   22   23   23   23   23   24   24   24   25   25   26   26   27   27   28   29   
The mean of a data set is the sum of the terms divided by the total number of terms. Using math notation we have:

    
So, the difference in mean will be:
                                             
Therefore, 'there are about 2 more students in each class at Oak Middle School than at Poplar Middle School' is the correct statement.
 
        
             
        
        
        
I agree to what the other person said! Good Luck!
        
             
        
        
        
20=x/3-8
28=3x
3x/3 = 28/3
X= 28/3