The area of a sector of a circles is calculated by the equation A = πr^2 (theta/360). From the data of the sector, we determine the radius of the circle. THen, we can calculate for the area of the circle.
16.4π = πr^2 (72/360)
r = 9.06
Area of circle = πr^2 
Area of circle = π(9.06)^2
Area of circle = 82π
        
             
        
        
        
     Four order pairs are ( 2, 5 ), ( 4, 8 ), ( 6, 11 ), ( 0, 2). All those I cited are whole numbers so that should help plot them, and from there get a ruler or straight edge and align all the dots to create the line for the equation. The equation you gave was the standard form which was created out of the formula to find a equation it's y = mx + b, there could be small variations made. How I know it's proportional is because all linear equations are. But if that's not enough I also know since there's a ratio or pattern that it follows and doesn't stray from. In more depth, porportional relationship is a ratio between y and x which is the same thing everytime shown if simplified.  
 
        
             
        
        
        
use vanilla ice cream with that it's the best
 
        
                    
             
        
        
        
It could. If you turn it into an experiment. Let's say you take 100 students from each grade, and you ask them if they exercise. And then you wanna create a graph. And find out out of those students how many of them exercise and how many of them do not. Then turn it into a percent.
I hope this helps. If you have any further questions on this or any other questions just ask. I am here to help you, as needed.
 
        
                    
             
        
        
        
Yes she is right. i turned it into a fraction which would be 18/15. then divide 18 by 15, which is 1.2 . then multiply 1.2 by 100