Circle A has a radius of 6 and a center of (2,5). Circle B has a radius of 3 and a center of (1,7). If circle B is translated by <3,1>, does it overlap circle A? If not, what is the minimum distance between points on both circles?

1 Answer
Jul 2, 2018

circles overlap

Explanation:

What we have to do here is compare the distance d
between the centres of the circles 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 <3,1>

(1,7)(1+3,7+1)(4,8)new centre of B

to calculate d use the distance formula

xd=(x2x1)2+(y2y1)2

let (x1,y1)=(2,5) and (x2,y2)=(4,8)

d=(42)2+(85)2=4+9=133.61

sum of radii =6+3=9

since sum of radii>d then circles overlap
graph{((x-2)^2+(y-5)^2-36)((x-4)^2+(y-8)^2-9)=0 [-40, 40, -20, 20]}