The calculator I had in high school offered three angle measurements: degrees, radians and gradians. Gradians? It turns out that a gradian is defined to be 1/4

The calculator I had in high school offered three angle measurements: degrees, radians and gradians. Gradians? It turns out that a gradian is defined to be 1/400th of a circle so right angles are 100 gradians instead of 90. They were defined during the French revolution (when else?) and are apparently still used in some European applications such as surveying. But given the importance of measurements such as 30° and 60° in mathematics (π/6, π/3 in radians) that end up being the rather ugly 33⅓ᵍ and 66⅔ᵍ in gradians, the measurement has not met broader acceptance. https://en.wikipedia.org/wiki/Gradian https://en.wikipedia.org/wiki/Gradian