The length and breadth of a 40 inch LED TV can vary slightly depending on the brand and model, but typically the dimensions are around 36 inches (91.44 cm) wide and 20 inches (50.8 cm) high. However, it's important to note that these dimensions are for the screen size only, and the overall dimensions of the TV (including the bezel and stand) will be larger.
Some popular brands that make 40 inch LED TVs include Samsung, LG, Sony, Power Guard, TCL, Vizio, and Hisense.