The area of a circle is increased by 800%. By what percent has the diameter of the circle increased?  Choose the correct option
A) 100%
B) 200%
C) 300%
D) 600%
E) 800%
A diameter of 2   it's radius = 1   it's area = (1^2)pi = 1pi   Answer A:   If we increase that diameter 100%, we have....   A diameter of 4   it's radius = 2   it's area = (2^2)pi = 4pi   This area has increased (4 pi - 1pi)/1pi = 3pi/1pi = 3 3  /1= 
<gadget id="calculator">3  /1</gadget>
<output>3</output>
3= 300%   Answer B:   If we increase the diameter 200%, we have...   A diameter of 6   it's area = 3   it's area = (3^2)pi = 9pi   This area has increased (9pi - 1pi)/1pi = 8 pi/1pi = 8 = 800%   ANSW800%R:800%
<result>E</result>
The area of a circle is increased by 800%. By what percent has the diameter of the circle increased?