| Описание: | Successive paper sizes in the series A1, A2, A3, and so forth, are defined by halving the preceding paper size. ISO paper sizes are all based on a single aspect ratio of square root of 2, or approximately 1: 1. 4142. The base format is a sheet of paper measuring 1 m? in area (A0 paper size). The most frequently used paper size is A4 (210 ? 297 mm). The international paper size standard, ISO 216, is based on the German DIN 476 standard for paper sizes. There have been many standard sizes of paper at different times and in different countries, but today there are two widespread systems in use: the international standard (A4 and its siblings) and the North American sizes. |