Eight Inches to Make Johnny Smile by Claire Davis

Metric prefixes range from factors of 10 -18 to 10 18 based on a decimal system, with the base (in this case the meter) having no prefix and having a factor of 1. History/origin: A centimeter is based on the SI unit meter, and as the prefix 'centi' indicates, is equal to one hundredth of a meter. Centimeterĭefinition: A centimeter (symbol: cm) is a unit of length in the International System of Units (SI), the current form of the metric system. It is also sometimes used in Japan (as well as other countries) in relation to electronic parts, like the size of display screens.

Another version of the inch is also believed to have been derived from the width of a human thumb, where the length was obtained from averaging the width of three thumbs: a small, a medium, and a large one.Ĭurrent use: The inch is mostly used in the United States, Canada, and the United Kingdom. One of the earliest definitions of the inch was based on barleycorns, where an inch was equal to the length of three grains of dry, round barley placed end-to-end. There have been a number of different standards for the inch in the past, with the current definition being based on the international yard. History/origin: The term 'inch' was derived from the Latin unit 'uncia' which equated to 'one-twelfth' of a Roman foot. There are 12 inches in a foot and 36 inches in a yard. An inch was defined to be equivalent to exactly 25.4 millimeters in 1959.

Definition: An inch (symbol: in) is a unit of length in the imperial and US customary systems of measurement.

Eight Inches to Make Johnny Smile by Claire Davis