Circle A has a radius of 2 and a center of (6,5). Circle B has a radius of 1 and a center of (3,4). If circle B is translated by <1,3>, does it overlap circle A? If not, what is the minimum distance between points on both circles?

1 Answer
Jul 22, 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 a translation <1,3>

(3,4)(4,7)new centre of B

to calculate d use the distance formula

xd=(x2x1)2+(y2y1)2

let (x1,y1)=(6,5) and (x2,y2)=(4,7)

d=(46)2+(75)2=4+4=82.83

sum of radii =2+1=3

since sum of radii>d then circles overlap
graph{((x-6)^2+(y-5)^2-4)((x-4)^2+(y-7)^2-1)=0 [-40, 40, -20, 20]}