Radius of 1 button = r = 3x
Fabric required to cover 1 button = Area of the circle
= 
= 
= 
Total number of buttons = x
Fabric required to cover 1 button =  
  
Fabric required to cover x buttons = 
 
 
Hence, fabric required to cover x buttons  sq. units
  sq. units
 
        
             
        
        
        
<u>Answer:
</u>
Expression x + 2my + z represents cost of order where x, y, z are cost of small , medium and large drinks (in dollars) respectively.
<u>Solution:
</u>
Given that  
Juan’s family ordered a small drink and m medium drinks.
Alex family ordered m medium drinks and a large drink.
Need to write an algebraic expression which shows total cost of both order in dollars.
Let’s assume cost of one small drink = x
And assume cost of one medium drink = y
And assume cost of one large drink = z
So now cost of order of Juan’s family is equal to cost of 1 small drink + cost of m medium drinks = 1  x + m
 x + m  y
 y
= x + my
And cost of order of Alex family is equal to cost of m medium drinks + cost of one large drink
= m x y + 1 x z
=my + z
So total cost of both order in dollars = x + my + my + z = x + 2my + z
Hence expression x + 2my + z represents cost of order where x , y , z are cost of small , medium and large drinks (in dollars) respectively.  
 
        
             
        
        
        
When you are finding the area, you multiply the length x the width. So for example, we have a rectangle that the length is 6 feet and the width is 4 feet. So, first of all we multiply 6x4= 24. Since its area don't forget it is Square Feet (or any other type of measurement).
Hope it helps!