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.
Gradian (gon)
The gradian, also known as gon or grad, was established in France following the French Revolution to promote a decimal-based system of angular measurement. In this system, a circle is divided into 400 gradians, resulting in a right angle measuring exactly 100 gradians. The gradian aimed to make calculations easier by matching the decimal metric system. While it did not gain universal acceptance, it remains in use within certain engineering and surveying practices, especially in France and parts of Central Europe. Its straightforward decimal approach is convenient, but degrees and radians are more widely used globally.