Circle A has a radius of #4 # and a center of #(6 ,2 )#. Circle B has a radius of #3 # and a center of #(5 ,7 )#. If circle B is translated by #<-2 ,2 >#, does it overlap circle A? If not, what is the minimum distance between points on both circles?

1 Answer
Jun 1, 2018

#"no overlap "~~0.62#

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"#

#"before calculating d we require to find the new centre"#
#"of B under the given translation"#

#"under a translation "< -2,2>#

#(5,7)to(5-2,7+2)to(3,9)larrcolor(red)"new centre of B"#

#"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)=(6,2)" and "(x_2,y_2)=(3,9)#

#d=sqrt((3-6)^2+(9-2)^2)=sqrt(9+49)=sqrt58~~7.62#

#"sum of radii "=4+3=7#

#"since sum of radii"< d" then no overlap"#

#"minimum distance "=d-" sum of radii"#

#color(white)(xxxxxxxxxxxxx)=7.62-7=0.62#
graph{((x-6)^2+(y-2)^2-16)((x-3)^2+(y-9)^2-9)=0 [-20, 20, -10, 10]}