Centimeter

Centimeter is a unit of length in the SI (International System of Units). Centimeter was the base unit of length in the now deprecated CGS (centimeter-gram-second) system of units. A centimeter is equal to one-hundredth of a meter. Centi is the SI prefix for a factor of 1/100. 

Technicians frequently choose SI prefixes for factors of 103, such as milli- and kilo-, for many physical values. However, the centimeter remains a practical unit of length for many everyday measurements. A centimeter is equivalent to the width of the fingernail of an average adult person.

There are 100 centimeters in a meter. In the other direction, a centimeter is equivalent to 1/100 meters. Moreover, there are 0.1 centimeters in a millimeter. So, a centimeter is equivalent to 10 millimeters. One inch is equal to 2.54 centimeters. On the other hand, one centimeter is equivalent to 0.393701 inches.

Symbol

The Centimeter is represented by the symbol “cm.” By that, other patterns of centimeters can be symbolized as follows,

Square centimeters – cm^2

Cubic centimeter – cm^3

History

The term centimeter was first used in the late 1700s. The centimeter is a part of the metric system. The metric system of measurement is primarily credited to the French. The French government officially adopted this system on April 7, 1795.

Inch

Inch is the British imperial and the United States customary systems of measurement in units of length. Inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb.  The word ‘inch’ was derived from the Roman 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. An inch is equal to 1/36 yard or 1/12 of a foot.

According to the international scales, there are 2.54 centimeters in an inch. In the other direction, an inch is equivalent to 1/2.54 centimeters. Therefore, one foot is equal to 12 inches. So, an inch is equivalent to 1/12 feet.

Symbol

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

History

The term Inch was first used in the early 14th century. In 1324, King Edward II of England declared that 1 inch equaled 3 grains of barley placed end to end lengthwise.

Kilometer

Kilometer is a unit of length in the SI (International System of Units). It is equal to one thousand meters. 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 a 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. In the other direction, 1 statute mile is equivalent to 1.60934 kilometers. A kilometer is also equivalent to 3281 feet. In reverse, 1 foot equals 1/3281 kilometers. Moreover, there are 1094 international yards and 0.540 nautical miles in a kilometer.

Symbol

Kilometer is frequently represented by the symbol ‘km’. In the US, UK, and Canadian militaries, the word “klick” is slang for the kilometer. By that, other patterns of kilometers can be symbolized as follows, 

Square kilometer – Km^2

Cubic kilometer – km^3

Kilometer per hour – km/hr

History

The term kilometer was first used in the 1800s. It was first recorded in 1800-1810. French maps were published in 1835 and scales in this map are shown in kilometers. 

Meter

Meter is the base unit of length in the SI (International System of Units). The term meter was originally derived from the Greek word “measure”.

As of 2019, the meter has been defined as the length of the path traveled by light in a vacuum during a time interval of 1/299792458 of a second where a caesium hyperfine transition frequency defines the second. 

The definition of the meter is that it fixes the speed of light in a vacuum to the exact value of 299,792,458 m/s. Following that, a meter equals 39.37 inches and 1609 meters is equivalent to a statute mile. 

Meters can be changed to other SI units using prefix multipliers based on powers of ten. For example, a meter consists of 100 centimeters, and one thousand meters equals a kilometer.

Symbol

The meter is represented by the symbol ‘m’. Following that, other patterns of meters can be symbolized as follows,

square meter – m^2

cubic meter – m^3

History

The French first originated the meter in the 1790s. On March 30, 1791, the French Academy of Sciences specified the length of a meter.

English word meters were first used at least in the beginning of 1797. In 1893, the metre was first measured with an interferometer by Albert A. Michelson.