How long is five centimeters?

5 cm is about the length of a knuckle.

Centimeter is the unit of length measurement, which is equal to one hundredth of a meter. The unit of length, abbreviated as cm. ， 1cm = 1/ 100m。 1cm (cm) = 10mm (mm) =0. 1dm (decimeter) =0.0 1m (meter).

The international system of units chooses seven independent quantities as the base quantity, and the first one is length. Its basic unit name is meter, the symbol is m, and centimeter is not an international unit.

Geometric measurement, also known as length measurement, is a science with relatively early start, rapid development and mature technology in China. China is a famous ancient civilization with splendid ancient civilization. Measurement and testing technology is an important part of this civilization. As a geometric quantity in measurement, it has a long history of development.