Latitude exact relationship of parallels and meridians with horizontal and vertical: both are complicated curves. On the sphere the normal passes through the centre and the latitude () is therefore equal to the angle subtended at the centre by the meridian arc from the equator to the point concerned. If the meridian distance is denoted by then where denotes the mean radius of the Earth. is equal to . No higher accuracy is appropriate for since higher-precision results necessitate an ellipsoid model. With this value for the meridian length of 1 degree of latitude on the sphere is (60.0 nautical miles).
Dell Latitude the C6x0, D6x0, and E64x0 lines, but as of 2015 this line has been discontinued and replaced by both the 5 series and the 7 series. The 15" "Premium" line was the 8 series, until the E-series merged this line with the 6 series (Model numbers being along the lines of C8x0 or D8x0). The "budget" line was the 5 series, but as of 2015 the 5 series and 7 series Latitude laptops are the primary lines of Latitude laptops. The 3 series has replaced the 5 series as the budget line. Dell has also since dropped the E from