The measurement of a television is taken diagonally, so a 50-inch, 16x9 screen is approximately 25 inches high by 44 inches wide. External dimensions differ slightly between manufacturers and models, but one popular model, the Samsung EH5000 LED television, is 44.8 inches wide, 26.4 inches high and 3.7 inches deep.
In addition to the physical space occupied by a television, the viewing distance should also be considered when choosing a set size. Digital Trends recommends a 50-inch screen for enjoyable viewing at distances between 6.25 feet and 12.5 feet.
The world's first LED flat panel television screen was developed by James P. Mitchell in 1977, although LED televisions did not become available to the general public until the release of the Samsung LN-T4681F in 2007.