269. You wish to measure the distance on a Mercator chart between a point in latitude 43°30'N and a point in latitude 40°30'N. To measure 30 miles at a time, where should you set the points of the dividers to obtain the most accurate measurement?

To accurately measure distance on a Mercator chart, set the dividers to span 30 minutes of latitude centered on the mid-latitude of the segment being measured. The mid-latitude between 4330'N and 4030'N is 4200'N, requiring a divider span of 4145'N to 4215'N.