A Glossary of Mathematical Terms - G
Geometric mean
The geometric mean of two positive numbers a and
b is 
.
Geometric sequence (or progression)
A sequence of numbers where the first one is repeatedly multiplied by a fixed number to obtain the following numbers of the sequence. the fixed number is acalled the common ratio.
Glide reflection
A composite transformation where a figure is reflected and then translated.
Golden rectangle
A rectangle where the ratio of its length to its width is 
.
Great circle
See Sphere.
Greatest Common Factor (G.C.F.)
Is the largest common factor betwen two or more numbers, that is the largest numbers that divides all the given numbers.
Grid
A tessellation of congruent squares used in coordinate systems or to measure distances, areas, etc.