Note: The Jerry Wahl Refernce Article on Double Proportion is an excellent resource. This article can be accessed from the resources icon.

In this part of Unit 2, you should become familiar with the specific techniques of double proportionate measure, where it should be applied, and how computations are done.

In this section on double proportionate measure, we will apply the things you have already mastered in Unit 1 on single proportionate measure, and extend them to encompass another common field problem. One where four corners or more are identified, and these are located in all four cardinal directions from a lost corner.

For this reason, double proportionate measure is often referred to as four-way proportion. This method of corner restoration is generally applicable to the restoration of a lost corner common to four townships . . .