Unless you're an architect or an engineer, it's probably been years since you last used a protractor in geometry class. But, now the semi-circular tool is showing up in some odd places around town ...

The protractor is contained in a paper envelope, which also holds a sheet of instructions written by Penfield. The envelope is imprinted: ARM PROTRACTOR AND GONIOMETER. It is also stamped: Cenco 88210 ...

This means that all these lines of longitude form circles that have the same radius—the radius of the Earth. Longitude is basically a way of breaking the sphere into 360 degrees. However, we don ...