From time to time, I teach a freshman level course on liberal arts math. In the section on similarity of figures, there are a few exercises about reading maps and estimating distances. My students saw this as a pointless exercise in the age of GPS and Mapquest. And my comments about being stuck with only a paper map in the boonies usually go nowhere.

Enter Google Earth and its “ruler” tool. I can have them look at a picture of the Pentagon, and with one side measured with the ruler tool, ask them to find its area by subdividing the pentagon into triangles. (Using technology always has the advantage of cranking up the conceptual level of a problem.) There are some interesting math lessons using Google Earth at www.realworldmath.org.