Circle of latitude can be calculated by a common sine or cosine function. The 60th parallel north or south is half as long as the Equator (disregarding Earth's minor flattening by 0.3%). A circle of latitude is perpendicular to all meridians. The latitude of the circle is approximately the angle between the Equator and the circle, with the angle's vertex at Earth's centre. The equator is at 0°, and the North Pole and South Pole are at 90° north and 90° south, respectively. The Equator is the longest circle of latitude and is the only circle of latitude which also is a great
Latitude ON a customizable, Linux-based Mobile Internet Device (MID) platform the laptop is able to boot almost instantly and view Email, document reader, calendar, contacts and access the Internet. First laptop models to include Latitude ON were E4200 and E4300 released in February 2009. Last laptop model introduced so far is Latitude Z600. Dell claims that battery life can be extended to days. Latitude ON Reader is similar to Dell's MediaDirect where the software is located in a separate partition on the system hard drive and has a dedicated button to power on. There are several versions of Latitude ON: Latitude ON