



 
Hi Gerry, I am going to show you how to calculate the percentage increase as you go from one circle to a larger circle. First however I need to decide what aspect of the circles you want to compare. Is it the areas or perhaps the radii, or the circumferences? I am going to look at two circles, one of radius 4 inches and the other of radius 5 inches.
Percentage increase is (the larger number  the smaller number)/(the smaller number) 100. Hence for these circles the percentage increase in the radii is
Hence there is a 25% increase in the radius going from a circle of radius 4 inches to a circle of radius 5 inches.
The area of a circle is r^{2} where r is the radius and hence the percentage increase in the area is
Hence there is a 56% increase in the area going from a circle of radius 4 inches to a circle of radius 5 inches. I hope this helps,  


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