Externally Tangent Circles
Source:
November 13, 2005
quadraticsgeometrytrapezoidnumber theoryrelatively primePythagorean Theoremalgebra
Problem Statement
Circles and are externally tangent, and they are both internally tangent to circle . The radii of and are and , respectively, and the centers of the three circles are all collinear. A chord of is also a common external tangent of and . Given that the length of the chord is where and are positive integers, and are relatively prime, and is not divisible by the square of any prime, find .