What is a rhumb line best described as?

• A. A line cutting all meridians at the same angle
• B. A line of constant direction
• C. The shortest distance between two points
• D. A line that follows a great circle

Answer: (A)

A rhumb line is a path on a sphere that keeps bearing constant, crossing every meridian at the same angle. This means your compass direction relative to true north stays fixed as you travel. On a Mercator map, such a line appears as a straight line, which is why navigators use it for steady, constant-bearing courses. It’s not the shortest route between two points—that distinction belongs to a great-circle path, whose bearing changes along the way. So describing it as crossing all meridians at the same angle captures its defining geometric property.