Convert inches to kilometers

Symbol

The inch is represented by the letters in or a double straight quotation mark (“). For example, 5 inches is written as 5 in or 5”. 

Description

Inch is one of the smaller units of length measurement in the British imperial and the United States customary system of measurement. This estimation is thought to have derived from the width of the human thumb. The word ‘inch’ was derived from the Roman word "uncia" (twelfth).

In the past, there have been multiple standards regarding the exact measurement of an inch. However, with the adoption of the international yard during the 1950s and 1960s, the inch has been based on the metric system and defined as exactly 25.4 mm.

So it is quite easy to convert centimeter to inch or in to cm. According to the international scales, there are 2.54 centimeters in an inch. So inversely, an inch is equivalent to 1/2.54 centimeters.

For inch to foot conversion, note that one foot is equal to 12 inches. So, while doing ft to in conversion just divide the inch digits by 12 since an inch is equivalent to 1/12 feet. For in to yard conversion, an inch is equivalent to 1/36 yard.

History

Inch was used in the Textus Roffensis in 1120. It is the only surviving manuscript from the Laws of Æthelberht (which dates to the early 7th century). It is the earliest known reference to the inch in England. 

King Edward II of England proclaimed in 1324 that one inch was equivalent to three barley grains put end to end lengthwise. But as the barley grains' size could not be fixed, there was a possibility of having error in standardizing inch by this defintion. Actually before the establishment of the international yard and pound, numerous definitions were used for inch.

In 1912, US and UK followed different definitions of inch measurement. Carl Edvard Johansson then reached a compromise. He produced gauge blocks with a nominal size of 25.4 mm that were accurate to within a few parts per million of both official standards. Because of the popularity of Johansson's blocks, several countries began using 25.4 mm as the inch between 1930 and 1964. It became known as the industrial inch. And this has since become the new official measurement of the inch. 

Use

Inch is mostly used in countries following the FPS (foot-pound-second) system of units. It is sometimes used for measuring small dimensions such as mobile display or electronic parts. 

Symbol

Kilometer is frequently represented by the symbol ‘km’. In the US, UK, and Canadian militaries, the word "klick" is a slang term of the kilometer.

Description

Kilometer is a unit of length in the International System of Units (SI). It is equal to one thousand meters. The kilometer is the preferred measurement unit to express distances between geographical places on land in most of the world. The United States and the United Kingdom are the notable exceptions where the statute mile is used.

A kilometer is equivalent to one thousand meters. So, one kilometer can be written in scientific notations as 1×10^3 m (engineering notation) or 1 E+3 m (exponential notation) — both meaning 10^3 × 1 m.

There are 0.621 statute miles in a kilometer. This means 1 statute mile is equivalent to 1.60934 kilometers. So to convert mile to km, multiply the mile with 0.621.

A kilometer is also equivalent to 3281 feet. In reverse, 1 foot equals 1/3281 kilometers. For calculation of km to yd (kilometer to yards), remember that there are 1094 international yards in a kilometer. If you want to convert nautical miles to km, then multiply kilometer value by 0.540.

History

The term kilometer was first used in the 1800s. It was introduced during the development and adoption of the metric system of weights and measures in France in the late 1700s.

The term "myriamètre"(preferring 10,000 meters) was used several times in 1802. It was used in the text of Develey's book Physique d'Emile: ou, Principes de la science de la nature.

It was first recorded as "kilometer' in 1800-1810. In 1835, French maps were published in which scales are shown in kilometers. The term "kilometer" first became an official unit in 1867  in the Netherlands representing 1000 meters.

Finally, the prefix "myria-" and the associated "myriametre" were officially removed by the International Committee for Weights and Measures (CIPM) in 1935, designating the term "kilometer" as the accepted unit of length for measurements.

Use

This is the go-to unit for expressing land distances, road length etc.