Apollonius' problem

Apollonius' problem

[‚ap·ə¦lōn·ē·əs ¦präb·ləm]
(mathematics)
The problem of constructing a circle that is tangent to three given circles.
References in periodicals archive ?
A generalization of Apollonius' problem is the following: find the number of irreducible conies (ellipses, parabolas, hyperbolas) which are tangent to 5 given circles.