What is the common difference measurement used to determine? lengths of lookouts spacing of collar ties lengths of gable studs spacing between common raffers

## Step 1<br />The common difference measurement is a term used in the context of construction, particularly in the construction of buildings. It refers to the consistent distance between certain elements in a building's structure.<br /><br />## Step 2<br />The options provided in the question are all related to construction, but the common difference measurement is most directly associated with the spacing of collar ties. Collar ties are horizontal members in a roof construction that help to prevent the roof from spreading.<br /><br />## Step 3<br />The common difference measurement is used to ensure that the collar ties are evenly spaced throughout the roof, which is crucial for the structural integrity of the roof.