Question 847348
If the diameter of circle A is twice the diameter of circle B, then the radius of A is twice the radius of B.<P>
Area is {{{pi*r^2}}}, so square the factor.  {{{2^2 = 4}}}  The area of the larger circle is four times the area of the smaller circle.<P>
Try it with a specific example.  A:  Diameter = 4, so radius = 2   B:  Diameter = 2, so radius = 1.<P>
Area A = {{{pi*2^2 = 4pi}}}<P>
Area B = {{{pi*1^2 = pi}}}<P>
Area A is four times area B.<P>