Hart's Theorem
Any one of the eight Apollonius Circles of three given Circles is Tangent to a Circle 
, as are the other three Apollonius Circleshaving (1) like contact with two of the given Circles and (2) unlike contact with the third.
References
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA: Houghton Mifflin, pp. 127-128, 1929.
- Bumping Algorithm
- Bundle
- Burau Representation
- Burkhardt Quartic
- Burnside Problem
- Burnside's Conjecture
- Burnside's Lemma
- Busemann-Petty Problem
- Busy Beaver
- Small Multiple Method
- Small Number
- Small Retrosnub Icosicosidodecahedron
- Small Rhombicosidodecahedron
- Small Rhombicuboctahedron
- Small Rhombidodecacron
- Small Rhombidodecahedron
- Small Rhombihexacron
- Small Rhombihexahedron
- Small Snub Icosicosidodecahedron
- Small Stellapentakis Dodecahedron
- Small Stellated Dodecahedron
- Small Stellated Triacontahedron
- Small Stellated Truncated Dodecahedron
- Small Triakis Octahedron
- Small Triambic Icosahedron