Arc Minute (′)
An arc minute (′) represents one-sixtieth of a degree, so a full degree contains 60 arc minutes and a complete circle has 21,600 arc minutes. Its origins trace back to ancient astronomers in Babylon and Greece, who needed finer subdivisions of the degree for celestial observations and mapping. Today, arc minutes are still fundamental in fields such as astronomy, navigation, and land surveying. They are commonly used in geographic coordinate systems—latitude and longitude—where they offer a more precise measurement than whole degrees.
Degree (°)
The degree, symbol °, is one of the oldest units of angle measurement, with origins in ancient Babylonian astronomy dating back to around 3000 BCE. The Babylonians used a base-60 (sexagesimal) number system, which is why a full circle was divided into 360 degrees; in contrast, a full circle is 2π radians. This division allowed for convenient fractions and calculations. Degrees became the standard in Greek, Arabic, and later European science, eventually spreading globally. Although radians are preferred in higher mathematics due to their direct relationship to circle geometry, degrees remain dominant in navigation, cartography, geometry education, and everyday contexts, making them one of the most recognizable and widely used angle units in history.