Q:

# Why does pi not have units?

A:

Pi does not have units because it is a number, not a measurement. However, pi is sometimes treated like a unit when referring to angle measurements because the actual unit, radians, is a length divided by length and is therefore dimensionless.

## Keep Learning

All "pure" numbers are defined as dimensionless quantities. These are the numbers that we use to count, including the irrational numbers like pi and e. Although some dimensionless quantities can have units (like radians), the units are only used when pure numbers are used to measure a quantity. Thus, it is possible to count to 100, but if discussing the length of a football field, it does not make any sense until a unit is added, for example, 100 yards.

Sources:

## Related Questions

• A: Pi is a mathematical constant and irrational number representing the ratio of a circle's circumference to its diameter with a value of approximately 3.1416... Full Answer >
Filed Under:
• A: Common math lessons for fourth grade math students include such topics as order of operations, units of measurement and rounding. Other popular topics incl... Full Answer >
Filed Under:
• A: One score is a unit of measurement equal to 20 units. The origin of the word is believed to be derived from the Old Norse word "skor," meaning to notch or ... Full Answer >
Filed Under:
• A: The symbol 3 is a numeral representing the number that is three units larger than zero. The same concept can be written in other ways, such as writing "thr... Full Answer >
Filed Under:
PEOPLE SEARCH FOR