Latitude constant latitude and constant longitude, which are constructed with reference to the rotation axis of the Earth. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface. Planes which contain the rotation axis intersect the surface at the meridians; and the angle between any one meridian plane and that through Greenwich (the Prime Meridian) defines the longitude: meridians are lines of constant longitude. The plane through the centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator. Planes parallel to the
Dell Latitude the Latitude line (due to switching to a USB C/Thunderbolt dock system, rather than the e-Port analog pin-system docks), and the models just go by number now, e.g.: Latitude 5480, 5570. The second number in the model (As in, 5470 or 7280) indicates the size of the screen in the laptop. The current Dell Latitude lineup is as follows: Latitude 3xxx series. Budget models intended for education or home office environments, available in 13.3"/14"/15.6" trims. Latitude 5xxx series. Mainstream line, available in 11.1"/12.5"/13.3"/14"/15.6" trims. Latitude 7xxx series. Premium "ultrabooks", available in 12.5"/13.3"/14" trims only. Latitude computers are also differentiated in