The key idea is locating a target in the horizontal plane using distance and direction from the observer. In polar coordinates, you describe where something is by its range—the straight-line distance from you to the target—and its azimuth—the horizontal angle measured from a reference direction (usually north) to the line pointing at the target. Together, range and azimuth pin down the target’s position relative to the observer. Other options don’t fit the same two-value description: a bearing is a directional angle like azimuth but longitude is a geographic coordinate, not part of the polar description; elevation and distance mix a vertical angle with distance, giving a 3D position rather than the simple 2D polar pair; latitude and longitude are global coordinates, not polar coordinates.