Circle A has a center at #(3 ,2 )# and an area of #16 pi#. Circle B has a center at #(4 ,7 )# and an area of #80 pi#. Do the circles overlap?

1 Answer
May 12, 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 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)=(3,2)" and "(x_2,y_2)=(4,7)#

#d=sqrt((4-3)^2+(7-2)^2)=sqrt(1+25)=sqrt26~~5.1#

#"to find the radii"#

#"circle A " to pir^2=16pirArrr^2=16rArrr=4#

#"circle B " to pir^2=80pirArrr^2=80rArrr=sqrt80=4sqrt5#

#"sum of radii "=4+4sqrt5~~12.94#

#"since sum of radii"> d" then circles overlap"#
graph{((x-3)^2+(y-2)^2-16)((x-4)^2+(y-7)^2-26)=0 [-10, 10, -5, 5]}