Meter is the fundamental unit of length and it is equal to approximately 39.37 inches. Historically defined as 1/10,000,000 of the quadrant of the Earth's circumference from the North Pole through Paris to the equator. This definition was set by the French Academy of Sciences. In 1889, the international prototype of a meter was the distance between two lines on a standard bar of 90% platinum and 10% iridium. In 1960, a meter was redefined to equal to 1,650,763.73 wavelengths of the orange-red line in the spectrum of the Krypton-86 atom in a vacuum. This definition was redefined again in the 1980s to the current valid definition. A meter is equal to the distance light travels in a vacuum in 1/299,792,458 of a second.
