When measuring distance, which scale should be referenced to the latitude where the distance is being measured?

The correct choice is the latitude scale, as it is specifically designed to provide accurate distance measurements based on the curvature of the Earth at different latitudes. When measuring distances on a map or chart, the latitude scale allows you to understand how distances translate in real-world navigation, as the distance between lines of latitude remains relatively consistent.

This is particularly important in marine navigation where understanding distances helps with navigation and positioning. Latitude lines run parallel to the equator and are crucial when plotting courses or determining positions relative to the Earth's surface.

Other scales such as longitude, nautical, and depth scales serve different purposes. The longitude scale is relevant to distances measured along the meridian, but it varies based on latitude. The nautical scale is useful for navigating specific nautical charts but does not provide direct distance measurement in relation to latitude. The depth scale is concerned with water depth, which is not related to measuring horizontal distances. Understanding how to use the latitude scale is essential for accurate navigation and distance calculations on nautical charts.