Circle A has a radius of 2 and a center of (8 ,6 ). Circle B has a radius of 4 and a center of (2 ,3 ). If circle B is translated by <-1 ,2 >, does it overlap circle A? If not, what is the minimum distance between points on both circles?

1 Answer
Jul 23, 2017

The circles do not overlap and the distance is =1.07

Explanation:

The coordinates of the center of circle B' after translation is

C_B'=(2,3)+<-1,2> = (1,5)

The distance between the centers is

C_AC_B'=sqrt((1-8)^2+(5-6)^2)=sqrt(49+1)=sqrt50=7.07

The sum of the radii is

r_A+r_B=2+4=6

As

C_AC_B' > (r_A+r_B), the circles do not overlap

The shortest distance is =7.07-6=1.07

graph{((x-8)^2+(y-6)^2-4)((x-1)^2+(y-5)^2-16)=0 [-8.66, 16.65, -2.97, 9.69]}