Two circles have the following equations: (x +3 )^2+(y -5 )^2= 64 and (x -7 )^2+(y +2 )^2= 81 . Does one circle contain the other? If not, what is the greatest possible distance between a point on one circle and another point on the other?

1 Answer
Mar 21, 2017

The circles overlap and the greatest distance is =29.2

Explanation:

The centers of the circle are (-3,5) and (7,-2)

The distance between the centers is

=sqrt((7+3)^2+(-2-5)^2)

=sqrt(10^2+7^2)

=sqrt(100+49)

=sqrt149=12.21

The radii of the circles are 8 and 9

The sum of the radii =8+9=17

As the distance between the radii is < than the sum of the radii. the circles overlap.

The greatest disnce is =12.2+17=29.2

graph{((x+3)^2+(y-5)^2-64)((x-7)^2+(y+2)^2-81)=0 [-28.85, 28.87, -14.43, 14.45]}