Circle A has a center at #(5 ,-4 )# and a radius of #7 #. Circle B has a center at #(-6 ,-8 )# and a radius of #5 #. Do the circles overlap? If not, what is the smallest distance between them?

1 Answer
Apr 1, 2016

overlap

Explanation:

First step is to calculate the distance between the centres using the #color(blue)" distance formula " #

# d = sqrt((x_2 - x_!)^2 + (y_2 - y_1)^2) #

where #(x_1,y_1)" and " (x_2,y_2)" are 2 coordinate points "#

let #(x_1,y_1)=(5,-4)" and " (x_2,y_2)=(-6,-8) #

# d = sqrt((-6-5)^2 + (-8-(-4))^2) = sqrt((-11)^2 + (-4)^2) #

#= sqrt(121 + 16) = sqrt137 ≈ 11.7#

now, radius of A + radius of B = 7 + 5 = 12

Since , sum of radii > distance between centres , circles
overlap.