Circle A has a radius of 3 and a center at (1,2). Circle B has a radius of 5 and a center at (3,7). If circle B is translated by <2,4>, does it overlap circle A? If not, what is the minimum distance between points on both circles?

1 Answer
Jun 3, 2018

no overlap 2.82

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 the translation <2,4>

(3,7)(3+2,7+4)(5,11)new centre of B

to calculate d use the distance formula

xd=(x2x1)2+(y2y1)2

let (x1,y1)=(1,2) and (x2,y2)=(5,11)

d=(51)2+(112)2=16+81=11710.82

sum of radii =3+5=8

since sum of radii<d then no overlap

minimum distance =d sum of radii

××××××x=10.828=2.82
graph{((x-1)^2+(y-2)^2-9)((x-5)^2+(y-11)^2-25)=0 [-20, 20, -10, 10]}