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

1 Answer
Apr 27, 2016

circles overlap

Explanation:

What we have to do here is calculate the distance (d) between the centres of A and B and compare this with the sum of the radii.

• If sum of radii > d , then circles overlap

• If sum of radii < d , then no overlap

Under a translation of ((2),(3))

centre of B(1 ,2) → (1+2 , 2+3) → (3 ,5)

Calculate d using the color(blue)" distance formula "

color(red)(|bar(ul(color(white)(a/a)color(black)( d = sqrt((x_2 - x_1)^2 + (y_2 - y_1)^2))color(white)(a/a)|)))
where (x_1,y_1)" and " (x_2,y_2)" are 2 points "

let (x_1,y_1)=(7,3)" and " (x_2,y_2)=(3,5)

d=sqrt((3-7)^2+(5-3)^2)=sqrt(16+4)=sqrt20 ≈ 4.472

radius of A + radius of B = 4 + 2 = 6

Since sum of radii > d , circles overlap