Circle A has a center at #(5 ,2 )# and an area of #18 pi#. Circle B has a center at #(3 ,6 )# and an area of #27 pi#. Do the circles overlap?

1 Answer
Feb 19, 2016

The circles do overlap (by #4.87# units)

Explanation:

Since Circle A has an Area #=18pi#,
Circle A has a Radius of #r_A = sqrt(18) = 3sqrt(2)~~4.24#
#color(white)("XXX")#(this follows from formua #"Area" =pir^2#)

Since Circle B has an Area #=27pi#
Circle B has a Radius of #r_B=sqrt(27)=3sqrt(3)~~5.20#

The distance between the center of A at #(5,2)# and the center of B at #(3,6)# is
#color(white)("XXX")d=sqrt((5-3)^2+(2-6)^2)=2sqrt(5)~~4.47#

Together the radii of circles A and B cover #4.24+5.20 = 9.34# of the line segment joining the centers of A and B.
Since this is greater than the actual length of the line segment joining A and B, the radii must overlap by #9.34-4.47=4.87# units.
graph{((x-5)^2+(y-2)^2-18)((x-3)^2+(y-6)^2-27)=0 [-14.11, 17.94, -3.74, 12.28]}