(1) the diameter is 20 inches whats the radius? And whats the circumference?
Radius is half the diameter, Answer: 10 inches
Circumference is pi times the radius, Answer: 10π inches
I won't bother with the approximation, though this one is easy, 31.4159 inches.  I'll leave the rest of the calculator work to you if necessary.
(2) the diameter 11 inches whats the radius? And whats the circumference?
Radius half, Answer: 5.5 inches.   Circ: 5.5π inches
(3) the diameter 3.5 inches whats the radius? And whats the circumference?
Radius, 1.75 inches.  Circ: 1.75π inches
 
        
             
        
        
        
Answer:
D
Step-by-step explanation:
To find the percentage we must first find the area of the circle:
We can find the radius of the circle using the distance formula;
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Now we calculate the area;
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To get the percentage we divide the area of the circle by the square’s are and multiply by 100;
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Answer:
Any more details? 
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
i think the value of y is 8
 
        
             
        
        
        
It is a function because every input has exactly one output. It passes the vertical line test. 
If you plotted another point at 2 hours it would no longer be a function bc 2 would be an input they had more than one output.