Prime (symbol) facts for kids
The prime symbol ( ′ ), double prime symbol ( ″ ), triple prime symbol ( ‴ ), and quadruple prime symbol ( ⁗ ) are special marks that look a bit like apostrophes or quotation marks. They are used in many different areas like mathematics, science, language studies (linguistics), and music.
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It's easy to confuse prime symbols with other similar-looking marks. For example, the prime symbol ( ′ ) is different from an apostrophe ( ’ or ' ), a single quotation mark ( ' or ‘ or ’ ), an acute accent ( ´ ), or a grave accent ( ` ).
The double prime symbol ( ″ ) is also different from a double quotation mark ( “…” or "…" ), a ditto mark ( ” ), or a letter double apostrophe ( ˮ ). Even though they look alike, these symbols have different meanings. Computers and printers treat them differently too.
Contents
Using Prime Symbols for Measurements
Prime symbols are often used to show measurements, especially for length and angles.
Measuring Length: Feet and Inches
The prime symbol ( ′ ) is commonly used to stand for feet (ft). The double prime symbol ( ″ ) is used for inches (in).
For example, if you see 3′ 5″, it usually means 3 feet and 5 inches. Sometimes, people use a regular single quote mark ( ' ) for feet and a double quote mark ( " ) for inches because they are easier to type.
Measuring Angles: Degrees, Minutes, and Seconds
Prime symbols are also used for very precise angle measurements.
- The prime symbol ( ′ ) can mean arcminutes (arcmin).
- The double prime symbol ( ″ ) can mean arcseconds (arcsec).
An arcminute is 1/60th of a degree, and an arcsecond is 1/60th of an arcminute. So, 3° 5′ 30″ means 3 degrees, 5 arcminutes, and 30 arcseconds. This way of measuring angles is very important in astronomy and navigation.
Other Uses of Prime Symbols
The triple prime ( ‴ ) has some special uses:
- In watchmaking, it represents a ligne. A ligne is a very small unit of length, about 1/12 of an inch.
- In old astronomy books, it sometimes meant "thirds." A third was 1/60th of an arcsecond.
The quadruple prime ( ⁗ ) was also used in historical texts. It meant "fourths," which was 1/60th of a third. This shows how detailed and precise measurements could be, even a long time ago!
See also
In Spanish: Prima (tipografía) para niños
