# geometric mean

The geometric mean of *n* numbers is the *n*-th root of the
product of the numbers.

Thus, in the case of two numbers, *a* and *b*, the geometric
mean is √(*ab*).

For example, the geometric mean of the numbers 4 and 9 is *x* = √(4
× 9) = √36 = ±6.

See also geometric sequence.