Circle A has a center at #(2 ,3 )# and an area of #8 pi#. Circle B has a center at #(11 ,7 )# and an area of #54 pi#. Do the circles overlap?

1 Answer
Jul 28, 2018

#"circles overlap"#

Explanation:

#"What we have to do here is compare the distance (d)"#
#"between the centres to the sum of the radii"#

#• " if sum of radii">d" then circles overlap"#

#• " if sum of radii"< d" then no overlap"#

#"To calculate the radii use the area formula "A=pir^2#

#r_(A)=sqrt8=2sqrt2" and "r_(B)=sqrt54=3sqrt6#

#"to calculate d use the "color(blue)"distance formula"#

#•color(white)(x)d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)#

#"let "(x_1,y_1)=(2,3)" and "(x_2,y_2)=(11,7)#

#d=sqrt((11-2)^2+(7-3)^2)=sqrt(81+16)=sqrt97~~9.85#

#"sum of radii "=2sqrt2+3sqrt6~~10.18#

#"Since sum of radii">d" then circles overlap"#
graph{((x-2)^2+(y-3)^2-(2sqrt2)^2)((x-11)^2+(y-7)^2-(3sqrt6)^2)=0 [-20, 20, -10, 10]}