How is the standard length for a meter defined?

Unit of length (meter): One meter is defined as the circumference of the earth through the North Pole, Paris, France, the equator and the South Pole back up to the North Pole divided by 40,000,000.

In 1889, a new international prototype was made of an alloy of platinum with 10 percent iridium, to within 0.0001 meter, that was to be measured at the melting point of ice.

Since this original definition of a meter, other more accurate methods have been used to define the distance of a meter. A current method is to use the following formula: a meter is the length of the path traveled by light in a vacuum during the time interval of: (1/299,792,458) of one second.

More Info: en.wikipedia.org

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41 Comments

Bill Coe

Jim Moser , Ian Sadler is correct. The question should read, "How was the standard length for a meter defined in 1791?"

Paul Greenslade

Metre, please. A Meter is what you put coins in to park on the street.

Steve McVey

Dee Dee Matthews, if you think a metre is 3 feet then you're the idiotic one.

Jim Moser

Please, read the whole explanation.

Ray Anderson

True if you lived in the 18th century. And it is spelt Metre!!

Joris van Pelt

The metre (Commonwealth spelling) or meter (American spelling; see spelling differences) (from the French unit mètre, from the Greek noun μέτρον, "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is currently defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.