Circle A has a radius of 2 and a center of (5,7). Circle B has a radius of 4 and a center of (3,2). If circle B is translated by <2,−1>, does it overlap circle A? If not, what is the minimum distance between points on both circles?
1 Answer
Oct 25, 2017
Explanation:
What we have to do here is
compare the distance (d) between the centres of the circles to thesum of the radii
∙ if sum of radii>d then circles overlap
∙ if sum of radii<d then no overlap We require to find the 'new' centre of B under the given translation which does not change the shape of the circle only it's position.
under a translation <2,−1>
(3,2)→(3+2,2−1)→(5,1)← new centre of B Note that the x-coordinate of the centres of both circles is 5 indicating that they lie on the vertical line x = 5
Hence d is the difference in the y-coordinates.
⇒d=7−1=6
sum of radii =2+4=6
since sum of radii =d=6
then the circles touch externally
graph{((x-5)^2+(y-7)^2-4)((x-5)^2+(y-1)^2-16)=0 [-20, 20, -10, 10]}