This is a Word document that has several example problems with worked out solutions for finding the Geometric Mean.
Glencoe

Geometric meaning of the geometric mean
Cut The Knot

This site discusses and actually proves why the altitude to the hypotenuse of a right triangle is the geometric mean of the segments of the hypotenuse. It also discusses the corollaries of the Right Triangle Altitude Theorem. There are also activities that the user can use to practice what was learned.
The University of Georgia, Dept. of Mathematics, by J. Wilson

A helpful scientific calculator that runs in your web browser window.
Holt Online Learning

An informative site on geometric mean
Geometric Nice?

This page shows the differences between the concepts of arithmetic and geometric means. It also gives applications (other than altitudes of right triangles) of when and how the geometric mean is used in reallife.
Math Toronto

Geometric mean help
Free Math Help

This site explains, in a very straight forward manner, the meaning of the geometric mean of two numbers, the Right Triangle Similarity Theorem, and the corollaries associated with it. There are also easy to follow, worked examples of each theorem.
Regents Exam Prep

This site gives a brief description of geometric mean and shows an interactive example of the material.
Math Warehouse

Provides the general formula for figuring the geometric mean of a set of numbers. Includes a simple example.
EasyCalculation.com
