Circle A has a center at #(2 ,2 )# and an area of #8 pi#. Circle B has a center at #(13 ,6 )# and an area of #49 pi#. Do the circles overlap?

1 Answer
Nov 27, 2016

No. Please see the explanation.

Explanation:

Let #Area_A = "the area of circle A" = 8pi#
Let #Area_B = "the area of circle B" = 49pi#
Let #r_A =# radius of circle A
Let #r_B = # radius of circle B

#Area_A = 8pi = pir_A^2#

#r_A = sqrt(8)#

#Area_B = 49pi = pir_B^2#

#r_B = 7#

Let #d =# the distance between the two centers#

#d = sqrt((13 - 2)^2 + (6 - 2)^2)#

#d = sqrt(11^2 + 4^2)#

#d = sqrt(137)#

This distance is obviously greater than the sum of the two radii but , Let's subtract #r_A and r_B#, to sure:

#sqrt(137) - 7 - sqrt(8) ~~ 1.876#

Therefore, the circles do not overlap.