Which statement defines a rhumb line?

• A. A line of constant latitude.
• B. A line of constant bearing that crosses successive meridians at the same angle.
• C. A curved line on a Mercator projection.
• D. The shortest distance between two points on the Earth.

Answer: (B)

A rhumb line is a path that you sail along with a constant bearing relative to true north. Because the bearing remains the same as you progress, the line crosses every meridian at a fixed angle. On a Mercator chart this shows up as a straight line, which is why rhumb lines are easy to chart and follow when steering a constant course.

This statement captures the essential idea: constant bearing and crossing meridians at the same angle. The other options describe related ideas but not the defining feature. A line of constant latitude is a parallel that doesn’t express the general notion of maintaining a single course relative to meridians. A curved line on a Mercator projection would imply changing bearing, not constant, and the shortest distance between two points on the Earth is a great-circle path, which generally requires changing bearings along the way.