In this second section of Unit 1, we will learn exactly what proportionate measurement is and how it can be applied to finding a lost corner. Then we will dive into our first method, single proportionate measure. Section 7-7 of the manual defines proportionate measurement as: Measurement that gives equal relative weight to all parts of the line. In its simplest form then proportionate measurement can be demonstrated as shown. These are the distances recorded by the original surveyor.

These are the measurements taken by a later surveyor in search of the original corner. The later surveyor has set a temporary stake at the record of 45.

But we know that the true distance, P, cannot be 45, if we are to apply the four-chain difference over the total length of the line as the manual and common sense would indicate.