Königsberg Bridge Problem
The Königsberg bridges cannot all be traversed in a single trip without doubling back. This problem was solved byEuler, 
and represented the beginning of Graph Theory.
References
Bogomolny, A. ``Graphs.'' http://www.cut-the-knot.com/do_you_know/graphs.html. Chartrand, G. ``The Königsberg Bridge Problem: An Introduction to Eulerian Graphs.'' §3.1 in Introductory Graph Theory. New York: Dover, pp. 51-66, 1985. Kraitchik, M. §8.4.1 in Mathematical Recreations. New York: W. W. Norton, pp. 209-211, 1942. Newman, J. ``Leonhard Euler and the Königsberg Bridges.'' Sci. Amer. 189, 66-70, 1953. Pappas, T. ``Königsberg Bridge Problem & Topology.'' The Joy of Mathematics. San Carlos, CA: Wide World Publ./Tetra, pp. 124-125, 1989.
- Guldinus Theorem
- Gumbel's Distribution
- Guthrie's Problem
- Gutschoven's Curve
- Guy's Conjecture
- Gyrate Bidiminished Rhombicosidodecahedron
- Gyrate Rhombicosidodecahedron
- Gyrobicupola
- Gyrobifastigium
- Gyrobirotunda
- Gyrocupolarotunda
- Gyroelongated Cupola
- Gyroelongated Dipyramid
- Gyroelongated Pentagonal Bicupola
- Gyroelongated Pentagonal Birotunda
- Gyroelongated Pentagonal Cupola
- Gyroelongated Pentagonal Cupolarotunda
- Gyroelongated Pentagonal Pyramid
- Gyroelongated Pentagonal Rotunda
- Gyroelongated Pyramid
- Gyroelongated Rotunda
- Gyroelongated Square Bicupola
- Gyroelongated Square Cupola
- Gyroelongated Square Dipyramid
- Gyroelongated Square Pyramid