Question 726484
C = d*pi  where d is the diameter.  The diameter of the first circle is 1, and its radius is .5 (1/2 the diameter.  The diameter of the second circle is 4, and its radius is 2.<P>
The ratio of the diameters is 1/4 (1:4)<P>
Area is {{{pi*r^2}}}.  For the first circle it's {{{pi*.5^2}}} = .25*pi.  For second circle it's {{{pi*2^2}}} = 4*pi.  The ratio is .25*pi/4*pi = .25/4 = 1/16.<P>
The ratio of the radii is .5/2 = 1/4.
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