What is a chain?
The chain is a unit of length measurement commonly used in surveying and land measurement. It is primarily used in countries that follow the imperial system of measurement, such as the United States and the United Kingdom. One chain is equal to 66 feet or 20.1168 meters. It is further divided into 100 links, with each link measuring 0.66 feet or 7.92 inches.
The chain was historically used for measuring large areas of land, such as farms or estates. Surveyors would use chains to measure distances between points and establish boundaries. The use of chains allowed for more accurate measurements compared to other methods available at the time. Today, the chain is still used in some specialized fields, such as civil engineering and land surveying, although it has been largely replaced by more modern and precise measurement tools like GPS.
What is an inch?
An inch is a length unit normally used in the United States and, occasionally, in the United Kingdom. It is defined as a twelth (1/12th) of a foot. The inch is normally subdivided into fractions of an inch such as the ½, ¼ and ⅛.
Historically, an inch was originally based on the width of a man's thumb. The inch is still commonly used in the United States for everyday measurements and worldwide for the size of TV and computer screens and clothing.
Inches are used in combination with other units of imperial measurement such as feet and yards. For example, a standard door in the United States a football field is 100 yards long or 300 feet or 3,600 inches.